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EXPERIMENTAL RESEARCHES

APPLIED TO

PHYSIOLOGY AND PATHOLOGY,

E.'BROWN-SEQUAfiD,

M. D, OK THE FACULTY OF PARIS, LAUREATE OF THE IXSTITUT DE FRANCE ( ACADEMIE

DES SCIENCES), EX-SECRETARY OF THE SOCIETE PIIILOMATIIIQUE, AND OK

THK SOCIKTE DE BIOLOGIE, OF PARIS, ETC.

NEW YORK:

II. BAILLIERE, No. 290 BROADWAY,
219 REGENT STREET, LONDON,

AND

RUE HAUTEFEUILLE, PARIS.
1853.

Entered, according to Act of Congress, in the year of our Lord 1853, by

II. BAILLIERE,

iu the Clerk's Office, of the District Court, of ihe
Southern District of New York.

TABLE OF CONTENTS.

Page.

I. On the source of the vital properties, . . .1

II. On the reflex faculty, .... 5

III. On the influence of the nervous system upon organic life, . 0

IV. On the reparative power of the nervous system, . 17
V. On turning and rolling produced by injuries of the nervous

system, . . . . . .18

VI. On a means of measuring degrees of anaesthesia and

hyperoesthesia, . . . . .23

VII. On the causes of the torpidity of the tenrec, . .25

VIII. On the influence of poisons upon animal heat, as a cause

of death, ..... 26

IX. Action of cold, warmth and light upon the crystalline lens, 29
X. On the normal degree of the temperature of man, . 30

XI. Influence of the temperature of one extremity on the tem-
perature of the body, . . . . 32

XII. Coagulability of blood, and its circulation in frogs, after

heart has been cut, . . . .35

XIII. On a singular case of animal graft, . . .30

XIV. On a convulsive affection produced by injuries of the

spinal cord, . . . . .36

XV. On the relations between the organization of nerve-tubes

and their vital properties, . . . 38

XVI. On the persistence of life in animals deprived of their

medulla oblongata, . . . . .40

XVII. Influence of the degree of animal heat on asphyxia, . 45

XVIII. On the central seat of sensibility, and on the value of cries

as a proof of pain, . . . . .54

XIX. On the mode of action of the most active poisons upon the

nervous system, . . . . .57

XX. On the crossing of action in the transmission of impres-
sions in the spinal cord, . . . .63

IV CONTENTS.

XXI. On muscular irritability in paralyzed limbs, and its semei-

ological value, . . . . .68

XXII. On the increase of animal heat, after injuries of the

nervous system, . . . . .73

XXIII. Cause of the stopping of the heart's movements, in

Weber's experiment, . . . .77

XXIV. On a singular action of air on the gray matter of the

spinal cord, in birds, . . . .79

XXV. On the treatment of epilepsy, . . . 80

XXVI. Cure of epilepsy by section of a nerve, . . .84

XXVII. Laws of the dynamical actions in man and animals, . 8G

XXVIII. Influence of red blood on muscles and nerves deprived of

their vital properties, . . . .88

XXIX. Cases of loss of sensibility on one side of the body, and

loss of voluntary movements on the other side, . 95

XXX. On the different degrees of excitability of the different

parts of the sensitive nerve fibres, . . .98

XXXI. The auditive nerve is a nervous centre, . . 99

XXXII. On apparently spontaneous actions of the contractile

tissues of the animal body, .... 101
XXXIII. On the cause of the beatings of the heart, . . 114

THE papers collected in this book have been published in the Medical
Examiner, of Philadelphia, from August, 1852, to August, 1853. They
form only a part of the author's original researches in Physiology and
Pathology. A second will soon be published, containing the results of
the author's experiments and clinical observations on some important
points of the physiology and pathology of the different nervous centres,
on fractures of the spine, on the vital properties of the iris and of the
cellular tissue, on the properties and functions of the blood, on the signs
of death, on electro-physiology, on the laws of cadaveric rigidity and-
putrefaction, and on the etiology and treatment of some of the nervous
diseases.

ERRATA.

Page 28, line 31 ; is at, read is not at.

" 54, " 15 ; animation, read diminution.

" 55, 1st note; Kay, read Fray.
Pages 58 & T5, A. Barnard, read C\ Bernard.
Page 73, 2d note; 1853, read 1852 ; and add or, ante Art. III., p. 9.

" 78, line 35 ; molar, read motor.

" " " 88 ; contraction of or, read contraction or.

" 103, " 13; after muscles, add of this last limb.

"[116, " 16; to account, read easy to account.

" 117, " 15 of the note ; any, read the.

tk " 2d note ; Bologne, read Biologie.

" 119, line 6 ; Does that, read Why does.

" " " 26 ; minutes, read times.

" " " 80 ; any, read a.

" 123, " 37 ; so, read very.

EXPERIMENTAL RESEAKCHES

APPLIED TO

PHYSIOLOGY AND PATHOLOGY

E. BROWN-SfiQUARD, M. D.,

OF PARIS/

[Reprinted from the Medical Examiner for August, 1852.]

I. — ON THE SOURCE OF THE VITAL PROPERTIES.

I think that every tissue possesses its vital properties, in con-
sequence of its peculiar organization, and that in a completely
developed animal, nutrition is the source of the vital properties,
inasmuch as it is the cause of the maintenance of organization.

I will try to prove the correctness of my opinion, by the fol-
lowing remarks on some of the vital properties of the spinal
cord, the nerves, and the muscles.

[* The paper which we have the pleasure of presenting to our readers
from Dr. Brown-Sequard, is a resume of many researches made by the
author, a part of which only have hitherto been published in any of the
foreign journals.

The conclusions arrived at are the result of eight years exclusive devotion
to the experiments upon which they are based. — EDS. Ex.]

a. — Source of the reflex faculty in the spinal cord.

Notwithstanding the experiments of Redi, Whytt, Procbaska,
Unzer, Sdnac, Fontana, Caldani, Sir G. Blane, Fray, Legallois
and many other experimenters; and notwithstanding the much
more important experiments of Marshall Hall, Muller, Grain-
ger, Volkmann, Kurschner, Pickford, de Martino, Buchner,
Mayer, Paton and Stilling, the existence of the reflex faculty,
after the spinal cord has been separated from the encephalon, is
not considered by all physiologists as a proof of the independence
of the spinal cord. J. W. Arnold and Flourens still maintain
that the medulla oblongata is a centre, giving life to the other
parts of the nervous system. The reflex faculty possessed by
the spinal cord after it has been separated from the encephalon,
is considered by J. W. Arnold as a remainder of something given
to the spinal marrow by the encephalon, before their separation.

My experiments prove the incorrectness of that opinion.* I have
found that after having exhausted the reflex faculty by putting
it in action, energetically and frequently, in an animal on whom
the spinal cord is separated from the encephalon, it reappears,
and becomes soon as energetic as before, provided that the cir-
culation of blood takes place in the cord. Moreover I have
found, that if the reflex faculty is put in action frequently, it is
able to produce an immense quantity of action : thus, for
instance, it can stimulate sufficiently the muscles of a frog's leg
to make them raise, in an hour and in divided portions, about twelve
pounds, to the height of about two lines. In a pigeon the reflex
faculty is able to stimulate the muscles of a leg so far as to make
them raise fifty pounds, by fractions, in an hour, to the height
of more than one inch.f

I shall add two other decisive proofs : — 1. The reflex faculty
is very weak in frogs immediately after the spinal cord has been
separated from the medulla oblongata, and it increases after-
wards, as R. Whytt and Marshall Hall have discovered. I have
stated that it increases so much that the posterior limbs are able

* See : — Recherches et experiences sur la physiologie de la moelle epi-
mere. These inaugurate. Paris, 3 Janvier, 1846. — Comptes rendus des
seances de 1' Academic des Sciences. Paris, 1847 T. xxiv. p. 849.

tSee Gaz. Med. de Paris. T. 4. 1849. p. 233.

to draw up, by reflex action, more than double the weight
the animal could raise up by an action of its will before the
division of the cord. 2. After having divided the spinal cord in
the dorsal region on a mammal, I kill it by cutting the right
carotid artery. A few minutes after the cessation of reflex
action I inject blood by the opening made in the carotid. Then
life returns and with it the reflex faculty.

All these facts demonstrate positively that the reflex faculty
is a vital property belonging to the spinal cord, and that its
source is in the nutrition which maintains the organization of that
nervous centre.

b. — Source of the vital property of the motor nerves.

The independence of the motor nerves is denied by almost all
physiologists. They believe that the nervous centres are the
sources of the vital property of these nerves. They base their
opinion on this fact, that the motor nerves separated from the
nervous centres soon lose their property, as it has been seen by
Fontana, Haighton, Astley Cooper, Steinrueck, Mu'ller, Sticker,
Giinther, Schoen, Kilian, Stannius, Helmholtz, Martin-Magron
and others.

But, in the first place, if the motor nerves of the warm-blooded
animals lose their vital property after having been separated
from the nervous centres, it is not less positive that they retain
it during several days. Secondly, if the vital property of the
motor nerves is exhausted by very energetic action, it re-
appears after a short time, although the nerves are separated
from the cerebro-rachidian centre, provided that the circula-
tion of blood continues in them. Thirdly, if the circulation
of blood is stopped in a limb in which the nerves have been
divided, it is found that the peripheric portion of the divided
nerves lose their vital property before the muscles. After the
nerves have been left dead, i. e., deprived of their vital property
for a quarter of an hour, half an hour, and even more, blood is
allowed to circulate anew in the limb. Then the vital property
of the cut nerves returns, and, to produce a muscular contrac-
tion, only a slight compression upon them is necessary.* If the

*See Comptes rendus de 1'Aead. des Sciences. T. xxxii. Seance du 9
Juin, 1851. — Gaz. Medic, de Paris. 1851. T. vi, p. 359.

motor nerves lose their property when they are separated from
the nervous centres, it is because they are then badly nourished.
Nerves as well as muscles must be exercised, in order to be
well nourished.

c. — Source of the muscular contractility.

Although there are some facts which appear strongly to prove
that the vital property of the muscular tissue is independent of
the nervous system, many physiologists persist in their opposi-
tion to Haller's doctrine on this subject. Therefore I have
thought necessary to add new proofs to those already known,
and I have published many experiments, of which I shall relate
here only two of the most decisive.*

1. The sciatic and the crural nerves having been resected, for
ten or twelve days, on a rabbit or a guinea-pig, I examine if these
nerves have completely lost their vital property, and if the
muscles are still contractile. When this has been ascertained, I
put a ligature around the aorta. Then muscular irritability dis-
appears after a certain time and cadaveric rigidity appears.
Three quarters of an hour or even an hour after the complete
disappearance of the muscular irritability, and the appearance of
the rigor mortis, I cut off the ligature, and I find, after ten or fif-
teen minutes, that the rigidity disappears and the contractility
reappears. I need not say that the nerves do not regain their
lost property. This fact clearly proves that the contractility is
given to the muscles by blood, i. e., by nutrition, and not by the
nervous system.

2. Many experiments have shown to me that muscles paralyzed
for five days or a little more, in consequence of the division of
their nerves, remain much longer contractile after the death of the
animal than the non-palsied muscles. This would hardly be the
case if the contractility was given to muscles by the nervous
system.

* See:— Bulletin de la Soc. Philomat. 1847, p. 74.— Gaz. Med. de Paris,
1851, t. vi. p. 619, and 1852, t. vii. p. 72.

II. — RESEARCHES ON THE REFLEX FACULTY.

During the last seven years I have published many papers re-
lating to the reflex faculty.* Among the facts which I have
discovered I will mention the following :

1. Grainger had found that the act of suckling can be exe-
cuted by an animal deprived of its brain. I have found that
even after the ablation of both the brain and the cerebellum,
newly-born rabbits are able to suckle very well; which is a
proof that suckling may be executed by reflex action.

2. It is commonly affirmed that the reflex power is much
stronger in cold-blooded than in warm-blooded animals. This
opinion is correct so far as regards the contrast between Mam-
mals and Batrachia (the animals usually compared) ; but it is
incorrect if Birds are compared with Reptilia and Fishes. It has
been said that the higher an animal is in the scale the less it
has reflex power. If this be true, we should find more and more
reflex power from Mammals to Fishes ; but the real order, ac-
cording to my experience is : 1st, Fishes; 2d, Mammals; 3d, Am-
phibia and Reptilia ; 4th, Birds ; so that Birds have more reflex
power than all the other animals, and Mammals have more than
Fishes. Of course, there are exceptions to this rule in the case
of particular species ; thus the eel, carp and tench have as
much reflex power as many Mammals possess.

It has also been commonly affirmed that the reflex power
diminishes with age, being the greatest in young animals. This
statement, also, has been based on a too limited induction. In
Reptiles and Fishes no difference can be detected in this parti-
cular. In Birds it is decidedly the other way, the reflex power
being much the strongest in adults. Among Mammals the dif-
ference is usually in favor of the young animal ; not, however,
at the very earliest part of its life, but ten or twelve days after
birth. As to man the reflex power appears to be greater in him
than in Fishes and Mammals ; but it is not so energetic as in
Birds and in Amphibia.

I have found that the causes of the differences between differ-

* See rny Inaugural Dissertation, Paris, 3 Janvier 1846, lere partie. —
Comptes rendus de 1'Acad. des Sciences, 1847, t. xxiv. pp. 363 et 859. — Gaz.
Med. de Paris, 1849, t. iv. pp. 430 et 644 ; et 1850 t. v. pp, 98 et 476.

ent animals, as regards the energy of their reflex power, are
to be explained by anatomical differences. There exists a con-
stant relation between the degree of the reflex power and the
amount of grey matter in the spinal cord. It appears, also,
that the mode of circulation of the blood in the spinal marrow
has a great share in the causes of differences amongst different
animals.

3. It is not necessary for the existence of the reflex power
that the spinal cord should be without alteration. I have found
the reflex faculty remaining in pigeons after I had crushed the
spinal cord, and produced in it a considerable alteration. This
is important to be known by practitioners, to prevent their
drawing the conclusion, from the existence of reflex action after
a fracture or a luxation of the vertebral column in man, that the
spinal cord is healthy.

4. The influence of the nervous system on the secretions, by
a reflex action, has been very little studied. I will state two
examples of these reflex secretions : 1st, There is on the face,
and particularly on the forehead and the nose, an abundant pro-
duction of sweat when the nerves of the taste are strongly
excited, as they are, for instance, by common salt, pepper, sugar,
etc. In certain persons the quantity of sweat produced in such
cases is sometimes, even in the winter, very considerable. 2d,
I have observed that it is sufficient to excite the nerves of taste
in order to produce the secretion of gastric juice, bile and pan-
creatic juice.

Ill RESEARCHES ON THE INFLUENCE OF THE NERVOUS SYSTEM

UPON THE FUNCTIONS OF ORGANIC LIFE.

My experiments have convinced me that if it is certain that
the nervous system is able to act, and frequently does act, on the
functions of organic life, it is not the less certain that the action
of the nervous system on these functions is not necessary. I
hope this will be sufficiently demonstrated by the numerous facts
I have to relate.

a. Influence of the section of nerves on nutrition and secretion.

1. The frequent occurrence of certain pathological changes
after section of the sciatic nerve in Mammals, has been cited as

a proof of the dependence of the nutritive operations upon
nervous agency. I think the following experiments give evi-
dence against that doctrine. I have divided the sciatic nerve
in a number of rabbits and guinea-pigs, and placed some of them
at liberty in a room with a paved floor, whilst I confined others
in a box, the bottom of which was thickly covered with bran, hay
and old clothes. In a fortnight, the former set exhibited an ob-
viously disordered action in the paralysed limbs ; the claws were
entirely lost ; the extremities of the feet were swollen, and the
exposed tissues were red, engorged, and covered with fleshy gra-
nulations. At the end of a month, these alterations were more
decided, and necrosis had supervened in the denuded bones. On
the other hand in the animals confined in the boxes, no such
injuries had accrued ; and although some of them have been
kept living for four, five and even six months after the division
of the sciatic nerve, no alteration whatever has appeared in the
palsied limbs except atrophy. In these cases a portion of the
nerve had been cut off, so that reunion was nearly impossible
and did not take place.

Experiments made on pigeons have given the same results.

It is obvious from these experiments that the pathological
changes which occur after the section of the sciatic nerve do not
proceed directly from the absence of nervous action, but that
they are consequent upon the friction and continual compression
to which the paralysed limbs are subject, against a hard soil,
owing to the inability of the animal to feel or avoid it.

In similar experiments made on frogs, I found that no altera-
tion took place, except when water penetrated through the
wound, under the skin, and between the muscles.*

2. With the help of an eminent micrographer (Dr. Lebert), I
have made researches on the influences produced on the capillary
circulation in consequence of the section of all the nerves (sym-
pathetic and cerebro-spinal nerves) in the legs of a number of
frogs. We have found no appearance of trouble in the capillary
circulation, neither in an hour, nor in three or four days after the
division of the nerves.

3. When resection of a long portion of one of the sciatic
and the crural nerves is made on a very young rabbit, guinea-

* See Gaz. Med. de Paris. 1849; t. 4, p. 880.

pig or pigeon, the palsied limb continues to grow in length, but
it grows only very little, if at all, in thickness. When the
experiment is made on all the nerves of the wing in a very
young pigeon, it is also found that the wing grows in length, but
very little in breadth or in thickness. The secretion of quills
takes place equally as well in the palsied limb as in the other.

The diiference in all these cases between the length of the
sound and that of the palsied limb or wing is never very consi-
derable ; nevertheless the length of the healthy parts is greater
than that of the paralysed parts.

4. I have found that burns, wounds and ulcerations existing
in parts palsied in consequence of the section of their cerebro-
spinal nerves, are cured as quickly and as well as those in sound
parts.

5. Atrophy is a constant consequence of the section of the
nerves of a limb. I have found that it supervenes not only in
the muscles and the bones, as J. Reid has discovered, but also in
the skin, which becomes evidently thinner.

6. Krimer asserts that after the section of the nerves of a
limb in Mammals, the venous blood is of a bright red color like
the arterial blood. (Physiologische Untersuchungen, Leipzig,
1820, p. 138 exp. 1, and p. 152 exp. 9.)

Long before the publication of Krimer, Arnemann had de-
clared that the blood appeared darker than usual in a limb on
which all the nerves had been cut. (Versuche iiber die Regera-
tion an lebenden thieren, Gottingen, 1786, t. i., p. 48.)

Longet (Traitd de Physiologic, Paris, 1850, t. ii., B. p. 92,)
says that he has seen the venous blood retaining its ordinary
color even three days after the section of the nerves of the
anterior limb in dogs.

Who is right — Krimer, Arnemann or Longet ? Neither of
them is perfectly right. The assertion of Arnemann is entirely
incorrect. By experiments made on dogs, rabbits, guinea-
pigs and pigeons, I have found that the venous blood in palsied
limbs is evidently less black than it is in sound limbs. But it is
not true to say that venous and arterial blood in paralysed limbs
have the same color. It is always very easy to distinguish one
from the other.

The transformation of the arterial blood into venous is not so

complete in the palsied as in the sound limb, but it always takes
place even in a great measure. There is a good proof of this
in the result of my experiments on the hand and forearms of
two decapitated men. I injected blood in the arteries of .these
parts thirteen or fourteen hours after death and when cadaveric
rigidity existed. Surely there was in that case no nervous
action whatever, and nevertheless the blood, which was of a
bright red color when injected, came out nearly black from the
veins !

From all these facts I shall conclude :

1st, That the nervous action (that of the sympathetic as well
as that of the cerebro-spinal nerves) is not necessary for the
change of color of the blood in the capillaries.

2d, That the nervous system of animal life has an influence
upon nutrition by which it takes a share in the transformation
of arterial into venous blood.

7. My friend Dr. Cl. Bernard has recently discovered the
curious fact, that after the section of the sympathetic nerve in
the neck, the face on the same side and more particularly the
ear, become warmer and more sensible than the other side. The
blood-vessels are much enlarged and a great many are visible
which were not so before the operation.

I have found that the remarkable phenomena which follow
the section of the cervical part of the sympathetic, are mere con-
sequences of the paralysis and therefore of the dilatation of the
bloodvessels. The blood finding a larger way than usual, arrives
there in greater quantity ; therefore the nutrition is more active.
Now the sensibility is increased because the vital properties of
the nerves are augmented when their nutrition is augmented.
As to the elevation of the temperature, I have seen, as Dr. Ber-
nard has, that the ear exhibits, sometimes, one or two degrees Fahr.
more than the rectum ; but it must be remarked that the tem-
perature of the rectum is a little lower than that of the blood ;
and as the ear is full of blood, it is very easy to understand why
it has the temperature of the blood. A great many facts prove
that the degree of temperature and of sensibility of a part, is in
close relation with the quantity of blood circulating in that part.

I base my opinion in part on the following experiments : If
galvanism is applied to the superior portion of the sympathetic

after it lias been cut in the neck, the vessels of the face and of
the ear after a certain time begin to contract ; their contraction
increases slowly, but at last it is evident that they resume their
normal condition, if they are not even smaller. Then the tem-
perature and the sensibility diminish in the face and the ear, and
they become in the palsied side the same as in the sound side.

When the galvanic current ceases to act, the vessels begin to
dilate again, and all the phenomena discovered by Dr. Bernard
reappear.

I conclude, that the only direct effect of the section of the
cervical part of the sympathetic, is the paralysis and conse-
quently the dilatation of the bloodvessels. Another evident con-
clusion is, that the cervical sympathetic send motor nerve fibres
to many of the bloodvessels of the head.*

8. Nearly all physiologists believe that the secretion of the
gastric juice is stopped after the section of the two pneumo-
gastric nerves. It is difficult to solve the question by experi-
ments on warm-blooded animals, because they die too quickly after
the section of the vagi. But it is not so with frogs. I have
found that they are able to live perfectly well either after the
extirpation of the medulla oblongata, or after the extirpation of
the ganglia of the par vagum. In both these cases I have found
that digestion continues to be performed. Consequently, if the
gastric juice is necessary to digestion, it is certain that this
liquid is secreted.f

* My experiments prove, also, that the bloodvessels are contractile, and
that the nerves are able to put them in action. I have also to remark that
it is a fact, well established by Budge and Waller, that the cervical sympa-
thetic is one of the motor nerves of the iris, and that the spinal cord is the
origin of the nerve-fibres going from the sympathetic to the iris. Some
experiments, which I intend to perform again, appear to prove that the
same parts of the spinal cord which give origin to some of the motor nerve-
fibres of the iris, originate also the motor nerve-fibres going from the cer-
vical sympathetic to the vessels of the head. Another conclusion is to be
drawn from the results obtained by Budge, Waller, Bernard and myself; it
is that the cervical sympathetic, instead of receiving its fibres from upwards
to give them downwards, received them downwards and distributes them
upwards.

~j~Comptes rendus de 1'Acad. des Sciences. Paris, 1847. T. xxiv. p.
363-64.

9. J. Reid has found, that if the four nerves uniting the spinal
cord to the posterior limbs are cut across on both sides, in
frogs, and if a galvanic current is applied every day to the pal-
sied limbs on one side, these galvanized limbs retain their natural
dimensions, while the palsied limbs not galvanised become
atrophied.

I have found : — 1. That if, instead of cutting only the four
cerebro-spinal nerves of the posterior limbs, I divide also the
branches of the sympathetic nerve which unite with them, the
same results are obtained as in Reid's experiment. 2. That if a
like experiment is performed on dogs, guinea-pigs, rabbits and
pigeons, the same results are found. 3. That if after atrophy
has taken place in the limb of a mammal or a pigeon, a galvanic
current is applied, every day, during several weeks, the atrophy
diminishes little by little and the limb at length becomes as large
as a sound limb. This happens although there is no return of
vital property in the divided nerves. 4. That if the application
of galvanism is made on the palsied limbs of very young animals,
and continued every day until they have arrived at adult age,
these limbs are then found to have grown as much, in every re-
spect, as the sound limbs.

In addition to these facts I have to state that in cases of lead
palsy, in which the extensor muscles, as far as I have been able
to judge, were completely destroyed and replaced by fibrous
tissue, I have seen muscles created by galvanism and becoming
as strong as they are in healthy men.

In a case, which I published two years ago, (Gaz. Med.
de Paris, 1850, t. v. p. 169,) I have found that an increase
of five centimetres in circumference took place in the superior
part of the leg of a young gentleman, under the influence of gal-
vanism, applied three quarters of an hour each day for six days.
In all the facts before related, galvanism acts by two ways :
the one is that it exercises the muscles, and increase in conse-
quence their nutrition ; the other is that it produces directly
some of the chemical changes which constitute nutrition.

The atrophy, which happens in paralyzed muscles, takes place
mostly because they remain without exercise, and partly because
when nervous action is deficient the respiration of the muscles is
not carried on as well as when the nervous system acts upon

them. Galvanism applied to a palsied limb acts partly in pro-
ducing the transformation of arterial into venous blood, i. e.,
what Gustav Liebig calls the respiration of the muscles. I have
seen frequently the venous blood, in palsied limbs, becoming as
black as normal venous blood, after the application of galvanism.
This change of coloration is not produced by a direct chemical
influence, exerted by galvanism on the blood, for if galvanism is
applied to blood in a vase, nothing of that kind is seen. It is in
consequence of an interchange between blood and the living
tissues that the change of color happens. The muscular con-
traction which takes place under the influence of the nervous
system, or that of galvanism, produces, in both cases, an increase
in the darkness of the venous blood. This fact proves that the
consumption of oxygen by muscles is increased during their
contraction.

I conclude from the preceding facts : —

1st. Nervous action is not necessary for nutrition.

2d. Atrophy in palsied limbs is more a consequence of absence
of exercise than of any other cause.

3d. Muscular atrophy, at any stage, may be cured by
galvanism.

b. — Influence of the nervous centres on nutrition and secretion.

1. Every one knows the singular alterations which take place
in the eye after a contusion of the frontal nerve, or a section of
the trigeminal or the cervical sympathetic nerves. Every one
knows also that the existence of worms in the intestinal canal,
and also certain affections of the spinal cord, are able to produce
morbid phenomena in vision, and even diseases of the eye,
and especially amaurosis. I have found that after the section
of a lateral half of the spinal cord, it sometimes happens that the
eye, on the same side where the cord has been wounded, will
present strange and various alterations. The part of the cord
having that influence on the eye, lies between the ninth and the
twelfth costal vertebrae. The alteration exists generally in the
cornea. In one case a ridge appeared on the anterior surface
of that membrane four days after the operation. On the fifth
day the ridge was deeper, and its edges had become opaque ; on
the sixth day all the cornea was opaque. It remained so for

five days, after which the opacity disappeared and no trace re-
mained of it, or of the ridge. This experiment has been made
on guinea-pigs.

2. I have found a considerable hypertrophy of the two supra-
renal capsules, on eight or ten guinea-pigs, upon which a lateral
half of the spinal cord had been cut in the dorsal region, for
eight, ten or fifteen months. These organs had acquired, in
some of these cases, three times their natural dimensions, and in
others only the double. There was no appearance of change in
their structure.

By an examination of the supra-renal capsules in guinea-pigs,
on which I had made the section of a lateral half of the spinal
cord, a few hours or a few days previously, I have found these
organs congested, and sometimes containing even a slight effu-
sion of blood. It is very probable that such a congestion has
been the cause of the hypertrophy found in animals operated on
at a much longer time previously. The congestion is certainly
the result of a peculiar disturbance in the nervous action. A
part only of the spinal cord appears to possess that singular
influence on the supra-renal capsules. That part is extended,
in guinea-pigs, from the tenth costal vertebra to the third lumbar.

A simple puncture of the cord is frequently sufficient to pro-
duce the congestion of both supra-renal capsules.

3. The researches, made before mine, as to the influence of
the spinal cord on the urinary secretion, could not give a decided
result, because no physiologist had been able to keep any warm-
blooded animal living a sufficient time, after the destruction of a
large part of the spinal cord.

The results obtained by S^galas on seme animals who have
lived from fifteen minutes to an hour after the destruction of the
lumbar part of the cord, had led him to conclude that the spinal
cord has no influence on the urinary secretion. Longet (Trait£
de Physiologic, Paris, 1850, t. ii. B. p. 199) says : — " Many ob-
servations have demonstrated to me that the visceral organs,
which receive their nerves from the sympathetic, are far from
being immediately paralyzed by the section of these nerves, and
that their action is even maintained much longer than the dura-
tion of the experiments in which Segalas had destroyed the spinal

marrow.* Therefore I think I am allowed to maintain that after
such an injury, the nerves going to these organs, and more par-
ticularly to the kidneys, do nothing but spend little by little
the nervous force, originally and principally derived from the
spinal marrow, which is the chief, if not the exclusive centre of
its production ; thence the persistence of the renal secretion, as
well as that of the movements of the heart, the intestinal canal,
the uterine cornua, etc."

I could relate a great many experiments proving the incorrect-
ness of Longet's theory, but a single one is sufficient. I have kept
living, nearly three months, a young cat, on which the spinal
cord had been completely destroyed from the eleventh or twelfth
costal vertebra to its termination. This cat has lived all that
time in apparently good health, and its urine has always been
perfectly normal. It was acid, as is the case constantly in cats
fed on meat, milk and bread. The bladder was palsied, but the
sphincter vesicae was generally contracted, so that every day I
had to compress the abdomen and the bladder to empty this
pouch. When I remained two days without doing that ope-
ration, the bladder contracted in consequence of the excitation
produced on its muscular fibres by their distension.

This fact clearly proves that the urinary secretion is not under
the dependence of the spinal cord.

According to Krimer, the medulla oblongata is the nervous
centre upon which the urinary secretion depends. My experi-
ments prove that this opinion is incorrect : — 1st. After the destruc-
tion of the medulla oblongata in frogs, I have found that the
secretion of urine remains as long as the animals have lived, i. e.,
three or four months. 2d. On hybernating mammals, in winter
time I have extirpated the medulla oblongata, after having
emptied the bladder. These animals have lived a little more
than a day, when I took the precaution of insufflating air in their
lungs many times each hour. After their death the bladder was
found full of urine apparently normal.

The medulla oblongata is not therefore a centre on which the
•urinary secretion depends.

4. The well known opinions of Segalas, W. Philip, Krimer,

* The italics are Longet's.

Chossat, Longet and others, about the influence of the spinal
cord on the functions of organic life, are quite erroneous. I have
found that birds are able to live for months after the destruction
of the spinal cord, from the fifth costal vertebra to its termina-
tion. This fact proves not only that the functions of organic
life may continue to exist in such a case, but that they appear to
be executed then as in healthy birds ; for, if the operation has
been made on a young bird, it will afterwards grow very well.

I have succeeded in keeping alive, from the 8th of April until
the 4th of July, a young cat, about which I have already pub-
lished a note in this journal.* The palsied parts in this animal
have grown in length proportionately as much as the sound parts.
The growth has been such in the palsied limbs that they have ac-
quired more than double the length they had at the time
of the operation. The functions of organic life appeared to
exist without any apparent disturbance. The nutritive reparation
was so powerful, that the pieces of the vertebral column which
had been cut off have been reproduced. This fact is important,
because it shows that the reproduction of bone is possible in a
palsied part.

The temperature of that cat was at the ordinary degree, (105°
.Eahr., in the rectum.) The secretion of the hair and nails took
place as in healthy cats. I had previously seen on birds that
their temperature remained normal after the destruction of a
great part of the spinal cord. Besides, I have found in these
birds that the secretion of quills and nails continued to take place.

As to the influence of the medulla oblongata on the functions
of organic life, my experiments on cold-blooded vertebrata have
proved to me, that these functions (except, of course, pulmonary
respiration,) may continue to exist without any appearance of
disturbance.

5. After the complete transverse section of the spinal cord in
mammals or birds, I have found that the ulcerations which take
place around the genital organs do not result directly from the ab-
sence of nervous action. One of the causes of these ulcerations
is continued pressure, and another cause is the continual pre-
sence of altered urine and faeces.

* See Med. Exam., No. v. May, 1852, p. 321.

My opinion is well proved by the following experiments : —

1st. I have put, three or four times a day and for many days,
a certain quantity of urine on the posterior part of the neck, in
the neighborhood of the scapulae, upon guinea-pigs. Before a
week elapsed, the skin, at the place acted on by the urine, had
lost its hair and epidermis. After a week more there was an
ulceration in the skin, and ten or twelve days later the skin was
destroyed, and there was an ulcer with a very bad aspect. This
fact proves how powerful is the action of urine on the skin.

2d. On guinea-pigs, upon which the spinal cord was cut in the
dorsal region, and on pigeons, upon which the spinal cord was
destroyed from the fifth costal vertebra to its termination, I have
found that no ulceration appeared when I took care to prevent
any part of their bodies from being in a continued state of com-
pression, and of washing them many times a day to remove
the urine and faeces.

3d. In cases where an ulceration had been produced, I have
succeeded in curing it by washing and preventing compression.

4th. I have found that in animals having the spinal cord cut
across, every kind of wounds or burns were cured as quickly as
in healthy animals.

Therefore the ulcerations which appear, in cases of paraplegia,
do not exist -directly in consequence of the palsy ; they can be
avoided and in many cases they can be cured.

These conclusions are perfectly true in animals having had
an injury to the spinal cord for a shorter time than a year ;
but on guinea-pigs, upon which a lateral half of the spinal cord,
had been cut for fourteen, fifteen, or eighteen months, near
the tenth or eleventh costal vertebra, I have found an alteration
of nutrition in the palsied parts. It was the right half of the
spinal cord which had been cut, and in such a case, as I have
discovered, the left side of the body behind the wounded part
evidently loses a portion of its sensibility, and its temperature is
also diminished. I have found, at the time designated, an ulcera-
tion coming in the part between the sacrum and the hip-joint.
That ulceration has taken a tolerably great extension in surface
but not in depth. It became as large as a half dollar.
The part ulcerated has never been subjected to any kind of
compression, neither to the action of urine and faeces.

Another kind of disturbance of nutrition occurred in these
animals : they lost the hair of the leg, and of the other parts in
which the sensibility was diminished.

6. It is known tliat erection is a frequent phenomenon in men
after a fracture or a luxation of the vertebral column. It is
known also, that in men hanged, erection and even ejaculation
are not uncommon. Segalas says he has seen these phenomena
produced by the excitation of the spinal cord. Longet (loco
cit., p. 201,) declares that he has not seen the excitation of the
cord producing such effects. It is very easy to ascertain, on
male guinea-pigs, that Segalas is right.

1st. A transverse section of the spinal cord always produces
an erection and an ejaculation.

2d. When one of these animals is asphyxiated, erection and
ejaculation take place.

3d. If the spinal cord is galvanized, erection and ejaculation
are produced.

These facts prove the influence of the spinal marrow on the
seminal vesicles. They empty themselves slowly when the cord
is galvanized.

In asphyxia, there are universal convulsions even in the mus-
cles of organic life, as uterus, intestine, etc. These last organs
are then put in contraction, and it is not astonishing, conse-
quently, that the seminal vesicles become also contracted. The
cause of these general contractions is the excitation of the spinal
cord by venous blood, and very probably by a large amount of
carbonic acid, as I will elsewhere try to demonstrate.

IV. — ON THE REPARATIVE POWER OF THE NERVOUS SYSTEM.

I have recently published in this journal* the results of my re-
searches on the reparative power of the spinal cord. From these
researches I have drawn the following conclusions : —

1st. That the spinal marrow, even in adult mammalia, may be
exposed to the action of the air without danger to the life of the
animal.

2d. That wounds of the spinal marrow may be repaired.

* Med. Exam., No. vi., June, 1852, p. 379.

3d. That after a complete transverse section of the spinal
cord, the functions of that organ may be entirely restored.

As to the nerves, the experiments of Fontana, Haighton,
Tiedemann, Flourens, Steinrueck, and many others, have de-
monstrated the possibility of reunion of the two extremities of a
cut nerve. But, in most, if not in all these experiments, the re-
turn of sensibility and of voluntary movements have not been
complete. The following fact is, consequently, very important,
because it proves the possibility of a complete reappearance of the
lost faculties after the entire division of a nerve.*

A guinea-pig, on which the sciatic nerve had been cut across,
exhibited indications of a return of sensibility a month after the
operation. Two months afterwards the sensibility was increased,
but was still much inferior to that of the sound limb. The mus-
cles then were beginning to contract under the influence of the
will. Six months after the section, the animal could evidently
move its legs and toes voluntarily ; the sensibility then was almost
entirely recovered. At the end of about eleven months, the
sensibility and all the voluntary movements were apparently
alike in the two posterior limbs. The animal having been killed,
it was found by my friend Dr. Lebert and myself that, except
a slight union of muscular fibres with the nerve at the place
where it had been divided, the restoration of the original condi-
tion was so complete that no indication of the division could be
discovered, either with the naked eye or with the microscope. I
had seen the usual swelling of the nerve at the point of reunion
about the sixth month after the operation, but at the time of the
last examination it had disappeared.

V. — ON TURNING AND ROLLING AS PHENOMENA PRODUCED BY
INJURIES OF THE NERVOUS SYSTEM.

Pourfour du Petit and Me'he'e de la Touche were the first expe-
rimenters who witnessed turning produced by an injury of the
nervous centres. But the first valuable researches on this phe-
nomenon were made by Magendie and Flourens.

The parts of the cerebro-spinal centre which can be injured
without producing turning, are : the cerebral hemispheres, the

*See Gaz. Med. de Paris, 1849, t. iv. p. 880.

cerebellum, the corpora striata, the corpus callosum, the spinal
marrow and the olfactive and optic nerves.* All the other parts
of the cerebro-spinal centres are able to produce turning or roll-
ing.

These circulatory or rotatory movements take place sometimes
on the same side, and sometimes on the side of the body opposite
to that of the encephalon which has been injured.

A puncture of one of the following parts produces turning or
rolling on the injured side :

1st. The anterior extremity of the thalami optici, according
to Schiff.

2d. The crura cerebri, according to Magendie.

3d. The bi, or quadri-geminal tubercles, according to Flourens.

4th. The pons varolii.

5th. The posterior part of the processus cerebelli ad pontem.

6th. The auditive nerve, according to my own experiments.

7th. The medulla oblongata at the point of insertion of the
facial nerve, according to my experiments in common with Dr.
Martin-Magron.

8th. The medulla oblongata outside of the anterior pyramids,
according to Magendie.

9th. A great part of the posterior face of the medulla ob-
longata, according to my experiments.

The parts of the encephalon which produce turning or rolling
on the opposite side, are :

1st. The posterior extremity of the thalami optici, according
to Schiff.

2d. The crura cerebri, according to Lafargue.

3d. The anterior part of the processus cerebelli ad pontem.

4th. A small part of the medulla oblongata before the nib of
the calamus scriptorius and behind the corpora olivaria, accord-
ing to my experiments in common with Dr. Martin-Magron.

Some of these two series of parts ordinarily produce turning
and the others rolling. But these two kinds of movements can
be produced by the puncture of a single part of the encephalon.
Rolling is nothing but the exaggeration of turning ; thus, after

* I consider as a part of the nervous centres, the three nerves of the su-
perior senses : the olfactive, the optic and the auditive.

a puncture of the medulla oblongata, the animal at first rolls, and
after some instants, instead of rolling, it turns. If, when it is
turning, a slight puncture is made anew, close to the first, then
the animal rolls.

Before trying to explain turning, I will give an outline of
some of its species.

1st. Turning and Rolling caused by tearing the facial nerve.

My friend Dr. Martin-Magron and myself have discovered
that if the facial nerve of a' rabbit or a guinea-pig be exposed at
its exit from the stylo-mastoid foramen, and be then drawn away
from the cranium, so as to tear it asunder near its origin, the
animal begins in about five minutes to turn itself round and
round, the movement being from left to right when the nerve
has been thus torn on the left side, and from right to left when
it has been torn on the right side. This rotation is generally
preceded by convulsive movements of the eyes, of the jaws, and
of the head upon the trunk : and the body is then bent (as in
pleurosthotonos) towards the injured side, by the contraction of
all the longitudinal muscles of that side, the power of which is
such as to resist considerable force applied to extend them. The
movement at first takes place in a small circle ; but the circle
generally enlarges more and more, until at last, after twenty or
thirty minutes, the animal walks in a straight line. There is no
paralysis of any muscles, save the facial. The effect is not pro-
duced, unless the nerve be torn close to its origin.

When the nerve on the other side also is torn, even after a
long interval, instead of the tendency to turn to one side, there
is, at first, a rolling of the body on its longitudinal axis, which
takes place towards the side last operated on. After this has
continued, however, for twenty minutes or more, the animal
recovers its feet, and begins to turn, as after the first operation,
but towards the other side. This movement soon ceases.

Dr. Martin-Magron and myself think that the cause of these
phenomena does not exist in the facial nerve itself, but in the
part of the medulla oblongata from which this nerve has origi-
nated.*

* See Gaz. Med. de Paris, 1849, t. 4, p. 879.

2d. Turning and Rolling produced by an injury to the Medulla

Oblong ata.

M. Magendie (Precis Ele'm. de Physiol. Paris, 1836, t. 1, p.
414) says : " Having raised up the cerebellum, I make a
section perpendicularly to the surface of the fourth ventricle and
at three or four millimetres from the median line. If I cut on
the right, the animal will turn on the right side ; if I cut on the
left, it will turn on the left side."

If we suppose a plane cutting the medulla oblongata transversely
at the distance of nearly two lines before the nib of the calamus
scriptorius, the posterior face of the medulla oblongata will be
divided into two parts : one before that plane, which I will call
superior, and the other behind, or inferior.

Now, every puncture on that superior part produces turning
or rolling on the side which has been punctured. The slightest
puncture on the processes cerebelli ad medullam oblongatam is
able to produce a violent and very rapid rolling. As long as the
animal lives after the operation, it rolls or it turns at each time it
tries to walk.

When (as Dr. Martin-Magron and myself have discovered) a
deep section is made on the inferior part of the posterior face of
the medulla oblongata, before the nib of the calamus scriptorius,
turning is produced on the side of the body opposite to the punc-
tured side of the medulla. A rabbit, which has lived thirteen
days after the operation, had still the circulatory movement a
few hours before dying. Nevertheless, sometimes the animal
could walk nearly straight during a few seconds.

3d. Turning Produced by a Puncture or a Section of the
Acoustic Nerve.

Flourens has discovered that, after the section of the semi-
circular canals, turning sometimes takes place.

I have found all the facts he relates about this subject perfectly
right. It was interesting to know if a puncture or the section
of the auditive nerve would produce turning. As it was impos-
sible to operate on that nerve in mammals, I have experimented
on frogs. In these amphibia it is easy to find the nerve and to
act upon it. I have found that after a puncture or a section on
the trunk of the nerve, the animal begins instantly to turn. As

long as the frogs live, after a puncture of the acoustic nerve, they
turn ; but the circle of turning is much smaller a short time
after the operation than afterwards. I have kept such frogs
for months.

4th. On a New Mode of Turning.

I have found a mode of turning which has altogether some of
the characters of turning and of rolling.

In the circulatory movement called turning (mouvement de
manege), the body of the animal is bent on one of the lateral
sides. It has the shape of an arch, and this arch is generally a
part of the circumference described by the animal when turning.
The smaller the radius of that arch, the smaller is the circle of
turning.

In the new mode of turning I have found, the body of the
animal is not bent, and when it walks it moves laterally,
instead of going forwards. In turning it describes a circle, but
the longitudinal axis of its body, instead of being then a part of
the circumference, is a part of a radius, so that its head is at the
circumference, and its tail towards the centre of the described
circle.

That mode of turning has been executed by animals on which
the quadrigeminal tubercles and the pons varolii, on one side,
had been punctured by a pin. One of the eyes was convulsed ;
the other was in its normal condition. The convulsed eye was
the right one, and the tubercles punctured were those of the
left side.

5th. On the Causes of Turning and Rolling.

I have not room enough to show that the theories of Magendie,
Flourens, Henle, Lafargue and Schiffare contradicted by a great
many facts. I will only present the following remarks :

1st. As the slightest puncture of certain parts of the encepha-
lon is sufficient to produce turning or rolling, it is evident that
those rotating movements do not exist in consequence of an
hemiplegia, as Lafargue, Longet and SchifF believe they do.
Another reason is that every degree of hemiplegia exist in man
without being accompained by turning or rolling. Besides, these
phenomena have been observed in persons who had no paralysis
at all.

2d. The theories of Magendie and Flourens are also opposed,
by the fact that a slight puncture is sufficient to produce turning
or rolling.

3d. As to the theory of Henle, which is based upon the
existence of convulsions in the eye, producing a kind of vertigo,
it has against it the facts that, on one side, convulsions may
exist in the eyes without any other disorder in the movements ;
and, on the other side, sometimes turning or rolling exist with-
out any convulsion in the eyes.*

Nevertheless, I think that, in many cases, the vertigo conse-
quent on convulsions of the eyes is one element of the cause of
turning. I think also that, in certain cases, paralysis of some
parts of the body may facilitate the rotatory movements. But
their great cause, I think, is the existence of a convulsive
contraction in some of the muscles, on one side of the
body. These convulsive contractions are to be found in
every case of circulatory or rotatory movement. As to the cause
of these contractions, it exists in the irritation produced in cer-
tain parts of the encephalon.

VI. — ON A MEANS OP MEASURING DEGREES OF ANAESTHESIA AND
HYPER^STHESIA.

The curious facts discovered by E. H. Weber, on tactile sen-
sibility, are well known. He found that if the two blunted
points of a pair of compasses are applied simultaneously on the
skin, there is, according to certain circumstances, either the
sensation of one or of two points. When the points are both
inside of certain boundaries, they are felt as one only ;
when they are outside of these boundaries, both are felt.
These boundaries vary exceedingly in different parts of the
skin, but for a given part the differences between men are
not extremely considerable. I have made use of the compasses
for measuring the degrees of tactile sensibility in diseases. In a
case of considerable anaesthesia of the lower extremities, the
patient only felt a single impression on one leg, although the

* See a very remarkable case observed by my friend Dr. Lebret, in
Comptes rendus et Memoires de la Soc. de Biologic annee 1850. Paris,
1851. t. ii. p. 7.

points of the compasses were ten, fifteen, or even twenty centi-
metres apart ; whilst on the other leg he could distinguish them
at a distance of twelve centimetres. The normal limit is gene-
rally, for that limb, from three to five centimetres. In another
case where anaesthesia was slighter, the limit of the discriminat-
ing power was at from nine to sixteen centimetres. In two other
cases, in which the diminution of sensibility had not been found
by the other means of diagnosis, the compass indicated a
very slight and beginning anaesthesia. The limit was at from
six to seven centimetres. •

These facts, and many others, have demonstrated to me that by
the help of the compass, a physician can ascertain : 1st. Whether
there is a slight anaesthesia or no. 2d. What is the degree of
anaesthesia. 3d. What changes occur every day in the amount
of anaesthesia.

The same is true for the cases of hyperaesthesia. In a case of
paraplegia of the motor power, the patient felt the two points of
the compasses, on his feet, even at the distance of five millime-
tres, whilst a healthy person feels the two points only when they
are at a greater distance than twenty-five millimetres.

I shall add, that for succeeding in such experiments the two
points must be blunted and applied simultaneously.*

* See Gaz. Med. de Paris, 1849, t. iv. p. 1012.

VII ON THE CAUSES OF THE TORPIDITY OF THE TENREC, (JErina-

ceus ecaudatuSj Linn.)

The influence of cold as a cause of hybernation has not been
considered essential, on account of an assumed fact, which is
altogether incorrect. This fact is that a mammal called the
Tenrec, (Erinaceus ecaudatus,~Lm.,) which lives in the Islands of
Mauritius, of Madagascar and Bourbon, is torpid under the
joined influences of warmth and dry ness. Cuvier says, about the
Tenrec : " They are nocturnal animals, remaining in lethargy
three months each year, although they inhabit the torrid zone.
Moreover, Bruguiere asserts that it is during the time of the
greatest heat that they are torpid." Physiologists have admit-
ted this fact as true, and they have supposed that warmth and
dryness could be, like cold, a cause of torpidity.

The following facts prove that the torpid sleep of the tenrec
takes place from precisely the same cause as that of the
hedge-hog, LErinaceus Europeus, Lin.,) and of other hyber-
nating mammals :

1st. The tenrec and the hedge-hog belong to the same
family, and they are much alike.

2d. According to MM. Desjardins, Telfair and Coquerel, and
to my own observations, the tenrecs earth themselves, and are
torpid from the month of June to the month of November, i. e.
during the winter season of the Islands where they live.

3d. Hybernating animals, belonging to varied species,
observed by Pallas, Mangili, Marshall Hall, Berthold, Barkow,
and myself, have been found torpid at the temperature of 61 to
66° F., (16 to 19° Cs.) Moreover, I have found that dormice,
(Mus glis., Lin.) even at a temperature of 6 S to 72° F., (20 to
22° Cs.) may become torpid, and I have observed some that
were constantly sleeping, during a whole week, at a tem-
perature varying from 59 to 68° F. (15 to 20° Cs.) I have
stated that hedge-hogs may be torpid during the summer ;
in Paris, at a temperature of 68 to 72° F., (20 to 22° Cs.) and
lately, in Philadelphia, I have seen a marmot (Arctomys monax,
Buff.) torpid, in June, at a temperature of 71 to 73° F. (21.5 to
23° Cs.)

4th. During the time of its torpidity, the tenrec is under

the influence of a temperature of 59 to 72 or 73° F., (15 to 22
or 23° Cs.) rarely more, and sometimes less. Therefore these
animals are exposed to a temperature sufficiently low to render
them torpid, for that temperature may produce that effect on
the hybernating animals of cold countries.

From these facts I believe it is right to conclude that torpidity
is induced in the tenrec, in the same way as in the other hyber-
nating mammals, and therefore it is not necessary to suppose
that warmth and dryness produce torpidity.

VIII ON THE INFLUENCE OF POISONS UPON ANIMAL HEAT AS A

CAUSE OF DEATH.

Provost and Chossat, and after them, M. Magendie, have
ascertained that death occurs quickly in mammals when their
temperature is notably diminished. My experiments confirm
the correctness of that statement. The diminution of animal
heat in mammals, is so dangerous that, in one case, I have seen
death take place in a rabbit after a diminution of only 22° F.
(12° Cs.) I have never observed any animal continuing to live
when I had diminished its temperature more than 44° F. (24°.5
Cs.) I have found the law established by Chossat perfectly correct,
according to which the diminution of animal heat necessary for
killing is less and less, in proportion to the rapidity with which
that diminution takes place.

It is very probable that in all the cases where, in consequence
either of disease, or of a wound, or of poison, the tem-
perature of man is diminished many degrees, his life is in
danger from the very fact of that diminution. It is thus in
cholera, in sclerema, in certain cases of palsy, in cases of great
disturbance of the respiration, in fractures and luxations of the
vertebral column, in the cervical, and even in the dorsal regions,
in cases of profuse haemorrhage, and in many cases of poisoning
when death is not rapidly produced.

It has been long known that temperature is diminished in
poisoned persons ; and there are but few cases of poisoning on
record in which it is not said that the patient was cold. Chos-
sat has found that a dog, into whose veins he had injected
opium, had its temperature diminished from 105° to 62.6° F.
(40°.3 to 17° Cs.), 22 hours after the injection. Brodie has

found that many poisons act upon animal heat so as to diminish
it considerably. Demarquay and Dume'ril, junior, and later,
these two experimenters, joined with Lecointre, have found the
same thing as Brodie in many toxic agents. I have made
very numerous experiments on this subject, and some of their
results have been published before the last papers of Demarquay,
Dume'ril and Lecointre.*

I have stated that many poisons, either injected in the veins
or absorbed by the vessels of the skin or of the digestive canal,
may diminish sufficiently the temperature of Guinea pigs
and rabbits, to produce death. This occurs when the dose of
the poison is not large enough to kill in less than four or
five hours. These poisons may kill only by their action upon
animal heat. It may be so with opium, cyanhydric acid, the
cyanide of mercury, hyoscyamus, digitalis, belladonna, tobacco,
euphorbia, camphor, alcohol, acetic, oxalic, sulphuric, azotic,
chlorohydric acids much diluted, and some oxalates.

Of course the action of these poisons is the greater, the colder
the atmosphere ; but it is not always immediately so, and in-
stead of diminishing the animal heat, many may increase it
for a time, especially when the temperature of the atmosphere
is elevated.

I have discovered that a dose of one of these poisons, suf-
ficient to kill an animal, when there is no obstacle to the dimi-
nution of its temperature, may be unable to destroy life when the
temperature of the animal is maintained by artificial means to
its normal degree, or not far from it. My experiments have
been conducted as follows :

Equal doses of poison were given, simultaneously, to two ani-
mals, as much alike one another as possible. One of them
was left in a room at a temperature of from 46 to 50° F. (8 to
10° Cs.), and the other was kept not far from a chimney, in a
place where the air was at from 75 to 86° F. (24 to 30° Cs.)
The first was dead after a certain number of hours, or sometimes
one or two days, having its temperature much diminished. The
other, on the contrary, had no perceptible diminution of its
temperature, and was generally cured very soon. Therefore,

* See Gaz. Med. de Paris, 1849, t. iv., p. 644.

when taken in certain doses, many poisons may kill only by
their influence on animal heat, and physicians, in cases of poison-
ing, should try as much to prevent the diminution of tempera-
ture, as to expel the poison or to act against it by an antidote,
by pulmonary insufflation, or otherwise.

In experiments which I have made lately on the action of
very pure digitaline, that had been prepared by M. Quevenne,
the celebrated chemist, who has made such interesting and
accurate researches on digitalis and the substances of which it
is composed, I have found that this poison may also dimmish
temperature. I believe it is easy to explain the contradiction
existing between Traube and Stannius, as regards the influ-
ence of digitalis on animal heat. When the atmosphere, in
which the animal is, is cold, then its temperature may be dimin-
ished by digitalis or digitaline, but when it is warm the diminu-
tion does not take place, or it is very small. But, of course, if
the dose is sufficient to kill very quickly, then it is indifferent
whether the atmosphere is cold or not, because there may be not
time enough for the diminution of the temperature of the animal.

I have to relate another fact which, I believe, ought to be
considered as analogous to the preceding. It is that kind of
poisoning which occurs when a layer of oil, of varnish or of
gelatin, is put on the skin of a warm-blooded animal. Death,
then, is very probably produced by a substance unknown
until now, and which is secreted by the skin. The layer of oil,
varnish, or gelatin preventing that secretion taking place, that
unknown substance becomes accumulated in the blood, and then
are produced the phenomena so well studied by MM. Fourcault,
Becquerel, Breschet, and Magendie. I have found that in
such a case the animals may live, if the atmosphere in which
they are kept is at a temperature inferior to 79 or 80° F. (26 or
27° Cs.) In these circumstances their temperature is not sensi-
bly diminished, while it diminishes much when the atmosphere
is cold. Therefore it is especially by their loss of warmth that
animals are killed, when their body has been entirely covered
with oil, varnish, or gelatin.

IX. — ON CERTAIN ACTIONS OF COLD, WARMTH, AND LIGHT UPON THE
CRYSTALLINE LENS.

Pourfour du Petit has discovered that after the death of a
mammal, it is not uncommon to find the crystalline lens opaque.
He has found also, that when the lens has become opaque, if we
draw it near the flame of a candle or a lamp, it becomes trans-
parent again after a few minutes. The same lens, put alter-
nately near and far from the flame, may become alternately
transparent and opaque. I have endeavored to discover whether
it is the light or the warmth of the flame which renders an opaque
lens transparent. I have placed between the lens and the flame
a layer of mineral salt, which is athermane and transparent.
Then the light of the flame could reach the lens, but not its
warmth. There has been no action. In another experiment I
have exposed to the light passing through the mineral salt a
fresh crystalline lens, still perfectly transparent. It became
opaque. Now, in a third experiment, I have compared two
crystalline lenses, perfectly transparent, one exposed to the
action of light passing through the mineral salt, and the
other kept in an obscure place. The former became opaque
much quicker, and considerably more than the other. There-
fore, 1st. It is not light which renders transparent an opaque
lens ; 2d. Light does not prevent a transparent lens from be-
coming opaque ; 3d. Moreover, light appears to accelerate, if
not to produce, the opacification of the crystalline lens.

As to the influence of warmth, it is certain that it is that
which renders transparent an opaque lens : 1st. When left in
the atmosphere, at a temperature superior to 70° F. (21° Cs.), a
fresh transparent lens remains transparent. 2d. When a lens
has become opaque, it is frequently sufficient to keep it exposed
to the warmth of the hand, during some minutes, to render it
transparent. 3d. The lower the temperature of the atmosphere
the quicker transparent lenses become opaque.

These experiments give a very interesting result, i. e., that
light appears able to produce an effect precisely opposite to the
effect produced by warmth.

From these researches I conclude :

1st. That light, and a low temperature, are favorable condi-

tions, if not direct causes, of the opacity of the lens in warm-
blooded animals after death.

2d. That a warm temperature, i. e , a temperature superior to
70° F. (21° Cs.) is & cause of the change occurring in the lens,
by which, when opaque, it becomes transparent.

I will add, that sometimes an analogous opacity takes place in
the cornea.

X. — ON THE NORMAL DEGREE OF THE TEMPERATURE OF MAN.

The degree of animal heat, in the human species, is stated as
being between 98.5° and 100° F. (37 and 88° Cs.) I intend to
prove that it is higher.

It is impossible to take directly the temperature of most of
the internal parts of the body in man ; therefore many physiolo-
gists, in order to discover the temperature of these parts, have
argued as follows : According to J. Hunter, the temperature
of the rectum in animals is the same as that of the right ven-
tricle of the heart ; hence it has been concluded that as the tem-
perature of the rectum, in man — still according to Hunter — is
98°.42 F. (36°.9 Cs.) the temperature of the internal parts of
the body ought to be between 98 and 99° F. (36°.67 and
37°.22 Cs.)

Some other physiologists, noting the temperature of the
mouth under the tongue, and supposing that this temperature
is nearly the same as that of the internal parts of the body, have
concluded that the temperature of man is between 99 and 100° F.
(37°.2 and 37°.8 Cs.) •

We will prove that these deductions are not right :

Firstly, the degree of the temperature of the rectum is not,
as Hunter says, 98°.4. It may be so in debilitated men, but in
healthy persons it is more elevated. It is between 100 and 102° F.
(37.7 and 38°. 89 Cs.) according to my own researches and to
those of Berger and Maunoir. Besides, many experiments on
dogs, rabbits and guinea-pigs, have shown satisfactorily to myself
that the temperature of the rectum is not equal to that of the
right ventricle. This last organ is from 1 to 3° F. (0.56 to
1.7° Cs.) higher than the rectum.

The temperature of the rectum, in man, being between 100
and 102° F. (37°.7 and 38°,8 Cs.), and the temperature of the

right ventricle, in man, being from 1 to 3° F. (0.56 to 1.7 Cs.)
higher than that of the rectum, if we suppose the same difference
existing in man as in mammals, it follows that the temperature
of the right ventricle of the heart in man ought to be between
101 and 105° F. (38°. 33 and 40°.56 Cs.)

But a closer approximation of the exact temperature of the
internal parts of the body, in man, may be obtained by taking
the temperature of an organ situated deeper than the rectum, and,
consequently, less exposed to the influence of the atmosphere.
Such is the case in the bladder. I have observed its temperature
by taking that of the urine at the moment of its emission and
before any sensible change had occurred in it. The urine was
directly received in a vase dipped into a large quantity of water
at 98° F. (36°.7 Cs.) Thus I have ascertained that the mean
temperature of the urine, in man, is 102°.6 F. (39°.2 Cs.)

Now if we take notice of this well-known fact, that the tem-
perature of the lower part of the abdomen is less elevated than
the upper part, we are authorized to believe that the temperature
of the central parts of the body, in man, is very near 103° F.
(39°.5 Cs.)

My experiments on the temperature of urine were made
on ten strong sailors, in the spring, on the Atlantic Ocean, be-
tween the 43d and 45th deg. of north latitude. The lowest de-
gree of the temperature of urine which I have observed, was
100°.9F. (38°.3Cs.); the highest was 103°.2F. (39°.56 Cs.)
My own urine, examined more than thirty times, in the most va-
ried conditions, has been nearly always at the same temperature ;
the variations have been only between 102° and 102°. 8 F. (38°.89
and 39°33 Cs.) The ordinary degree is 102°.5 F. (39°.17 Cs.)

Long before my researches, the temperature of urine, in the
human species, had been taken by some observers, but in general
without sufficient care. The temperature of the urine is 94°.25,
according to Braun; 98°.9, according to De Lisle; and 103°,
according to Hales. Recently Berger has taken the tem-
perature of urine in the bladder in five women. He has found
it equal to 101°,48 F. (38°. 6 Cs.)

As the temperature of woman is a little inferior to that of
man, the result obtained by Berger is in accordance with mine.

If we take the average between the temperature of the urine of

man as I have found it, and that of woman as Berger has found
it, we have a number very near 102° F. (38°. 9 Cs.)

From these facts we draw the conclusion that the temperature of
the thoracic and abdominal viscera, in the human species and in
both sexes, is between 102 and 103° F. (38^.89 and 39°.44 Cs.),
i. e., some degrees higher than it is generally admitted.

XI. — ON THE INFLUENCE EXERTED UPON THE GENERAL TEMPERA-
TURE OF THE BODY BY A CHANGE IN THE TEMPERATURE OF ONE
OF THE EXTREMITIES.

The following sentence is given, as an axiom, by Dr. W. F.
Edwards : « We cannot either raise or lower the temperature of
any one part of the body, without all the other parts of the frame
being affected and suffering a corresponding rise or fall in tem-
perature, more or less, according to circumstances."*

Expressed in such terms, we accept this law as perfectly true.
But the author elsewhere gives an extension to this law, which
we will prove to be incorrect. No doubt when the temperature
of the blood, coming to the heart from a remote part of the
body, has been modified in that part, the thoracic viscera ought
to have their temperature modified ; but to what extent ? It is
on this very important point that we do not agree with Dr.
Edwards. He was of opinion that the influence exerted by a
small part, on all the other parts of the body, was considerable.
He says that the chilling of a single part, such as the hand or
the foot, may cause a loss of temperature in all the other parts
of the frame, even far beyond what could have been presumed as
likely or possible, and that in a number of experiments where one
hand was plunged in water cooled down by ice, the other hand,
which was not subjected to the action of the cold bath, lost
nearly 5° H. (11°.25 F., 6°.25 Cs.) in temperature.

It will be easily understood how important it would be that
practitioners should be able to act on the general temperature of
a patient, so as to increase or diminish it, by means of a hand or
a foot bath. I ,regret to say that if the facts observed by
Edwards are exact, his conclusion nevertheless is incorrect.

* Article Ani?nal Heat, in Todd's Cyclop, of Anat. and Physiol., 1839,
t. ii., p. 660.

I have performed, both alone, and with the help of Dr.
Tholozan, Physician of the Hospital Val-de-G-race at Paris,
numerous experiments, with the view of knowing whether Dr.
Edwards was right or not. I have found that the chilling of
one hand plunged in water at the temperature of freezing point,
acted very strongly on the temperature of the other hand. But,
at first, there is no regularity at all in the quantity of degrees
of temperature lost by the hand which remains out of the water;
and secondly, ^ye have found once that this hand did not lose
any fraction of its temperature. In one case we have observed
that the hand kept in the atmosphere did lose 22° F. (12° Cs.)
in seven minutes. The ordinary loss of temperature has been of
between 6 to 8° F. (3.33 to 4°.44 Cs.) In one case there has
been only a loss of 2° F. (1°.2 Cs.) In another case there has
been no loss, and, on the contrary, there has been an increase of
temperature of 1°.4 F. (0°.8 Cs.)

If, like Edwards, we consider the loss of temperature of the
hand not plunged in water as a sign and as a measure of the
diminution of the general temperature of the body, we must
conclude, from our experiments, that the chilling of a small part
of the body may be unable to diminish the temperature of the
body sensibly, and that, in other cases, it may act extraordinarily
upon it. But the supposition that the hand kept in the atmos-
phere, was able to give a measure of the modification of the body
is incorrect. By taking the temperature of the mouth during the
time that one hand was dipped into very cold water, Dr. Tholo-
zan and myself have ascertained that the temperature of the
body does not sensibly change. The greatest diminution of the
temperature of the mouth has been nearly 1° F. (Op.6 Cs.),
and this only in one case. In that experiment in which the
hand not plunged in water lost 22° F. (12° Cs.), the tempe-
rature of the mouth was not diminished more than the fifth of
a Fahr. degree.

As it is quite certain that the temperature of the body is con-
stantly changing, it is easy to understand why we do not find a
small but a constant diminution in the temperature of the
mouth when one hand is subjected to a notable chilling. When,
under the unknown influences that are constantly modifying the
temperature of the body, there is a tendency to increase that

temperature, then the tendency to its diminution originating
from the chilling of one hand may exist without producing any
effect. We have there two causes acting in opposite directions,
and if they are equal they annihilate each other. If they are
unequal, we perceive only the difference between them. When
these two causes act in the same direction, then their efforts are
added to one another, and it is probably in a circumstance of
that kind that I have once found a diminution of 1° F. (0.°56C,)
taking place in the mouth.

We have now to examine how the diminution of the temperature
of a hand is produced when the other hand is dipped into cold
water. A priori it is evident that the chilling of the hand kept
in the air exists in consequence, either of the arrival of a cooler
blood, or in the diminution in the quantity of blood. That hand
being exposed to a cold air (for it is only in such a case that the
experiments succeed) loses its temperature by the action of that
cold air. At first the blood that arrives in the hand is not
cooler, as Edwards had supposed it was. This we prove by the
fact that the temperature is but very little changed in the mouth.
The supposition then remains that the quantity of blood ar-
riving in the hand is smaller than usual. This may happen by
two modes, one of which is that the heart sends less blood, and
the other that the blood-vessels of the hand are contracted and
prevent, in part, the passage of blood. It is certain that the
heart continues perceptibly to send the same quantity of blood.
Therefore we are induced to admit that the hand's blood-vessels
are contracted. But now what is the cause of that contraction ?
We will try to show that it is in an action of the nervous sys-
tem. Every one knows that under the influence of a sensation
or of emotion, the hands, and sometimes the feet, become cold.
The nervous system, in consequence of that sensation or emotion,
acts upon the blood-vessels and excites them to contract. The
calibre of the visible vessels is sensibly diminished. The same
phenomena take place in the two hands when one is dipped into
very cold water. An exceedingly violent pain is felt, the nervous
centres are strongly excited, and they act then as under the in-
fluence of an emotion. Dr. Tholozan and myself have observed
that the greater the pain felt, the more the temperature was di-
minished in the hand left in the air.

35 i

. As to the influence of partial heating Dr. Edwards relates
the following experiment :

" The hand being immersed in water heated to the temperature
of 34° R. (lOS^.SF — 42°.5Cs.) rose one degree of the same
scale, and the temperature of other remote parts not imme-
diately exposed to the influence of heat were found to have risen
to a corresponding degree."

I have repeated this experiment of Dr. Edwards, and I have
found no evident elevation in the temperature of remote parts, as
the mouth and the hand, not immersed in water.

I conclude, then from the facts contained in this note, that, in
general, the temperature of the body is not sensibly modified
by the chilling or the heating of a small part of the frame.

XII. — ACTION OF COLD ON THE COAGULABILITY 0F BLOOD, AND
PERSISTENCE OF LIFE IN FROGS AFTER LOSING HALF OF THE
VENTRICLE OF THE HEART.

Dr. Marchal (de Calvi) and other physiologists, have recently
asserted that cold diminishes the quantity of fibrine and conse-
quently the coagulability of blood. I have observed a curious
fact, which shows that blood may possess a very great coagula-
bility although exposed to the action of cold. I have found that
after the removal of the half of a ventricle, in frogs, the
blood may coagulate at the surface of the wound and the ani-
mal may continue to live. After the mutilation has been made,
the lips of the wound are drawn upwards and inside in conse-
quence of the muscular contraction. The blood flows very
abundantly, but its coagulation quickly begins, and a layer of
solidified blood is soon formed on the entire surface of the sec-
tion, and by this process the wound is rapidly obliterated. The
hemorrhage has been frequently stopped in a few minutes.

This experiment is successful only in cold seasons, probably
because the batrachia are able to bear much better a loss of
blood at a low than at a high temperature. The pulsations of
such mutilated hearts continue with regularity and strength, but
the impulse given by the remaining of the ventricle ought to
be diminished. Nevertheless the circulation of blood is accom-
plished well enough to allow the animal to live many months.

I have shown to the Societe de Biologie at Paris, two frogs on-
which the wound of the heart was cicatrised after fifteen days.*

XIII. — ON A SINGULAR CASE OF ANIMAL GRAFT.

Every one knows the experiments by which the cock's spurs
or many other animal textures have been grafted on the body of
an animal, and especially on a cock's comb. I have succeeded
in grafting the tail of a young cat on a cock's comb. I per-
formed this experiment in France in 1850.

After having divided the tail of a young cat, I made a longi-
tudinal section on a cock's comb, and I united these two parts
one to the other, by stitching the cut surface of the cat's tail to
the cut surface of the cock's comb. The skin of the cat's tail
had been turned a little over itself, so that its internal surface
was in contiguity with the cut surface of the cock's comb. Eight
days after, I punctured the skin of the tail at a distance from
the cock's comb, and blood escaped, so that it was evident that cir-
culation was already established. The tail had been cold during
all the day of the operation, but it became warmer gradually
from the second day. The union appeared much advanced on
the third or fourth day. The tail was entirely fixed on the
eighth day.

Unfortunately, on the eleventh day, the cock had a fight with
another cock, and the cat's tail was torn out from the ground
on which it had been fixed. I was thus deprived of the
opportunity of knowing what transformations should have taken
place in the tail.

By examining it I found that all its tissues were fresh, and
that its blood-vessels contained blood.

XIV. — ON A CONVULSIVE AFFECTION PRODUCED BY CONSIDERABLE
INJURIES OF THE SPINAL CORD.

I have discovered that a very violent convulsive affection is
the constant result of a considerable wound of the spinal cord,
in certain animals. It is more especially in guinea-pigs in whom
a transversal section of a lateral half, or a complete section of

* See Gaz. Med. de Paris, 1850, t. v. p. 169.

the spinal cord has been made, that this is the case.* The section
was made at the level of one of the last six dorsal vertebrae or
the two first lumbar.

When the convulsive fit begins, the muscles of the face and
neck are the first which contract. The convulsions occur alter-
nately in all the muscles of the eye, the face, the tongue, the
jaws and the neck ; so that the cause of these movements ought
to act on the parts of the encephalon, from whence the facial,
the trigeminal, the hypoglossus, and the motor nerves of the
eyes originate. The head of the animal is alternately bent
on both sides of the body, and lastly the limbs are agitated
in every direction. In the case of a section of the lateral
half of the spinal cord, in the lumbar region or at the end
of the dorsal region, three limbs only are strongly convulsed ;
the two anterior and one of the posterior — the one that is on
the side of the body opposite to the side of the section of the
spinal marrow. The other posterior limb has only very slight
movements. When the spinal cord has been entirely divided in
the dorsal or lumbar regions, the two anterior limbs only are
convulsed, with the muscles of the face and neck. These con-
vulsions may come without any exterior excitation ; but it is very
easy generally to provoke them by frightening the animal, or
by pinching, burning or otherwise exciting it. The part of the
body upon which a mechanical excitation acts more powerfully
is the skin of the face or the neck. This convulsive affection
has a great analogy with epilepsy ; but it has also some dis-
tinctive features, — for instance, the animals, during the convul-
sions, do not appear to lose their consciousness, and they
frequently cry when they are pinched.

The affection begins generally eight, ten or twelve days
after the spinal cord has been wounded. The convulsions then
are not very strong, and it is usually four or five weeks after
the operation that the fits are violent and easily produced.
Three or four months after, the violence and frequency of these
convulsions are diminished ; yet in two or three instances they
have increased in strength and frequency more than a year after
the operation. The affection may last a long time: in one case
it still existed two years after the operation.

* See Gaz. Med. de Paris, 1850, t. v. pp. 651, 895.
4

Generally the fits last from five to fifteen minutes. The
stronger they are the shorter is their duration. For an hour or
two, and sometimes for one or two days after a violent fit, it is
impossible to produce another one by any kind of excitation.
When a fit takes place a short time after a violent one, it is
always weak or very short.

I have made the following experiment on some guinea-pigs
having this convulsive affection : I put them in a small box, so
that they had but little room to move, and I gave them food
in great abundance. They then ate very much and were
deprived of exercise, and, in consequence of that mode of living,
they had exceedingly frequent convulsions. One of them had
a fit nearly every quarter of an hour. These fits sometimes were
strong, but they did not last long. The others had fits three or
four times every day. I changed their mode of living, and
put them all in a large room where they had only a small quan-
tity of food. The influence of this new regimen was nearly
immediate ; the same day the number of fits was diminished,
and in the course of the third week afterwards they had only
one or two fits ; and before long some of them were cured.

I must relate also a very interesting fact analogous to the
preceding. In several guinea-pigs and frogs, which had the
spinal cord transversely divided, I have observed that when the
animals remained very quiet during many days, instead of the
regular reflex movements, they had a violent tetanic convulsion
in their posterior limbs, when the skin of these limbs was
pinched.

Such a tetanic movement never occurred in these animals
when I excited the regular reflex movements every day.

I have no room in this resume to try to explain the facts
related ; I will do it in a special paper. I will only add that all
the readers of this note, who know the views of Dr. Marshall
Hall about convulsive diseases, will remark how strongly the
facts I have pointed out are confirmatory of these views.

XV ON THE RELATIONS EXISTING BETWEEN THE ORGANISATION

OF NERVE TUBES AND THEIR VITAL PROPERTIES.

It is well known that when the nerve tubes are examined in a
very fresh state, their contents, the medulla^ or white substance of

Seluvann, appear pellucid and homogeneous, and of a fluid con-
sistence ; but a kind of coagulation soon takes place in that me-
dulla, making it easily distinguishable from the tube itself, solid,
grumous and much less transparent. Water has the power of
producing very quickly that kind of coagulation of the white
substance of Schwann, and the more quickly the warmer it is.

It was interesting to ascertain whether a nerve-fibre keeps or
loses its vital properties when its contents have been transformed
by coagulation. I have performed two series of experiments in
order to solve this question ; one on the motor nerves, the other
on the nerves of sensibility.

1st. After having amputated the two limbs of a frog, I laid
bare a long portion of the sciatic nerve in both. Half an hour
afterwards these two nerves were still able to act perfectly
well. Then a microscopical examination of some fibres from
one of these nerves demonstrated that the coagulation of the
medulla had begun, but was not yet complete. Ten minutes
later the nerves were still capable of acting, and the microscope
showed that the coagulation was complete. A similar experi-
ment repeated a great many times has always furnished the
same result.

2d. After having divided the two sciatic nerves, not far from
the knee-joint, in a living frog, I have dipped the central part
of these nerves into water. After a few minutes, some fibres
taken from one of them were beginning to coagulate ; yet these
nerves possessed their sensibility. Ten minutes after, there was a
complete coagulation of the medulla, while the sensibility was
very little if at all diminished.

I draw from these facts the conclusion that nerve-fibres are
capable of acting nearly as well when their contents are coagu-
lated, as when they are still liquid.

This result appears to be important, inasmuch as it contri-
butes to show that the white substance of Schwann has not a great
part in nervous action. Three reasons concur in demonstrating
that the essential part, the truly active one — that which pos-
sesses the vital properties — is not the white substance of
Schwann :

1. We see that the vital properties of the nerve-fibres do not

appear altered, although there is a very material change in this
substance when it coagulates.

2. If such a change as that which takes place in this sub-
stance when it coagulates, existed in a part possessing the vital
properties belonging to nerves, there should certainly be a
movement or a sensation accompanying it, and yet there is none.
This material change is certainly more considerable than the
change effected by a slight mechanical or galvanic excitation,
which is capable of producing a movement or a sensation.

3. The microscope has already proved that the white sub-
stance does not exist in all the nerve-fibres, and that it is want-
ing, for instance, in the very fine fibres.

Therefore if it be not the white substance of Schwann which
is active in the nerves, and as it is not the cylinder axis which
possesses the vital properties of the nerves, because it is wanting
in many fibres, it results that it is the membranous layer, the
paries of the nerve-tube, to which these vital properties belong,
unless there is another substance, still unknown, and existing in
the tubular canal of the nerve-fibre.

XVI ON THE PERSISTENCE OF LIFE IN ANIMALS DEPRIVED OF

THEIR MEDULLA OBLONGATA.*

I. There is no part in the nervous system considered as more
essential to life than the medulla oblongata. In the last few years
many German physiologists have asserted that this nervous
centre is the source of the rhythmical movements of the heart.
Besides, an eminent physiologist maintains that in the medulla
oblongata a small part exists which is the focus of vital power.
Moreover, it is certain that the medulla oblongata has a great
share in the respiratory movements. Therefore it seemed pro-
bable that the ablation of such an organ, even in cold-blooded
animals, ought to be speedily followed by death. Such is not,
however, the result of that operation ; and in favorable condi-
tions, the batrachia, for instance, can live more than four
months after the loss of the medulla oblongata. During all that
time, these animals, in appearance remain in good health, and I
have observed in them the existence of all the following func-
tions and properties :

* See the Bulletin de la Soc. Philomatique. Paris, 1849, p. 117.

1. The circulation of blood continues as well as in un-
mutilated frogs. The beatings of the heart are at -first quick-
ened generally during half an hour, an hour or an hour and a
half, after the operation; they then return to their normal
rhythm, and they are found as regular and vigorous in frogs de-
prived of their medulla oblongata, for several days or even
several months, as in healthy frogs. Sometimes, particularly
when the hemorrhage has been considerable, the beatings of the
heart become less numerous and less energetic ; then the animal
dies very quickly, but if it lives, the movements of the heart re-
suiae before long their normal rhythm and strength.

2. The pulsations of the four lymphatic hearts take place as in
healthy frogs.

8. Digestion seems to be carried on as well and as quickly in
frogs without medulla oblongata as in healthy frogs. I have
ascertained this fact by introducing pieces of earth-worms into
the stomach of these animals, and by studying the changes pro-
duced in these aliments during their passage along the digestive
canal. Although very slow, chymous transformation, absorp-
tion and the production of faeces took place.

4. The products of the gastric, intestinal, biliary and pan-
creatic secretions being very useful, if not essential to digestion,
it is very probable that these secretions exist.

5. The urinary secretion and also the production of cutaneous
and intestinal epithelium, are performed as usual.

6. The pulmonary respiration ceases, but the cutaneous respi-
ration is continued. The absorption of poisons by the skin and
by the mucous membranes exists as in healthy frogs.

7. The reflex faculty is energetic, and so much so that the
frogs deprived of the medulla oblongata can raise by a reflex
action, greater weights than healthy frogs. As reflex movements
exist, I need not say that muscles and nerves have kept
their vital properties. It is frequently found that the spinal
cord, especially in the rana temporaries, becomes so excitable
that the slightest irritation of the skin is followed by tetanic
convulsions.

8. The galvanic current of muscles not only exists in frogs
deprived of medulla oblongata, but appears to be stronger.

From these facts it results clearly that frogs, deprived of

their medulla oblongata, are in full life. It is so much so that
if they are compared to frogs possessing that nervous centre,
they resist etherisation longer, and also live longer after the
ablation of the heart.

II. The greatest differences exist in the duration of life, after
the removal of the medulla oblongata, in animals of different
species, as will be seen in the following table, where the maxi-
mum duration of life is indicated in sixty different species of
animals :

Classes. Species.

f Salamanders

Amphibia. ) Frogs .....
( Toads .

Duration of life.
More than 4 months.
4 to 5 weeks.

Reptilia.

Fishes.

Birds.

Tortoises . . . . 9 to 10 days.

Snakes . , . . 6 to 7 days.

Lizards . . . . 4 to 6 days.

Eel 6 days.

Pike, carp, tench, eel pout, barbel 3 days.

Perch, gudgeon and others . 25 to 40 hours.

Sparrowhawk (newly born) . 21 minutes.

Magpie do. . 19 minutes.

Sparrow do. . 17 minutes.

Sparrow, yellowhammer, linnet, pi-
geon, fowl, duck, pintaw, par-

tridge,'moor-hen, turtle-dove (adult) 2| to 3 minutes.

29 hours.
23 hours.
46 minutes.
41 minutes.
34 minutes.
6 minutes.

4 minutes.

c Dormouse (during hybernation)
Hedgehog ditto

Bull-dog (newly born)
Cat ditto

Mammals.* j Rabbit ditto
Guinea-pig ditto
Dormouse and Hedgehog awaken in

summer ....
Cat, rabbit,guinea-pig and dog (adult) 3 to 3| minutes.

The preceding table shows that after the removal of the me-
dulla oblongata, in different species of animals, the duration of
life may be reckoned by months for batrachia, by weeks for some
reptilia, by days for other reptilia and for fishes, by hours for

* Pulmonary insufflation has been used only for the dormouse and
hedgehog during hybernation.

hybernating mammals, and by minutes for birds and non-hyber-
nating mammals.

III. After the removal of the medulla oblongata, the most
remarkable differences in the duration of life, in different indi-
viduals belonging to the same species, may occur in consequence
of differences of temperature. The lower the temperature the
longer is the duration of life. Thus, the duration of life in
frogs may be reckoned by months when the temperature is be-
tween 32° and 46° F., (0 and 8° Cs.) ; by weeks when it is
between 40° and 55° F. (5° and 13° Cs.) ; by days when it is
between 50° and 65^> F. (10° and 18° Cs. ) by hours when it is
between 65° and 72° F. (18° and 24* Cs.) ; and by minutes when
it is between 86° and 105^ F. (30° and 40° Cs.)

In the other cold-blooded vertebrata the differences in the
duration of life, after the removal of the medulla oblongata, are
not so great as in frogs, but the law is the same. This law
exists also for warm-blooded animals, so much so that the differ-
ences existing between mammals of different ages and of differ-
ent species, are to be attributed, in part, to their differences of
temperature.

IV. As the principal condition for a long duration of life
in cold-blooded vertebrata is a cold atmosphere, and as the
vital phenomena taking place in these animals are much dimi-
nished when they are exposed to a low temperature, some phy-
siologists have supposed that the persistence of life for many
weeks or more, was equivalent, as regards the sum of the vital
phenomena, to a duration of some hours in summer, when these
phenomena have a great activity.

In answer to this objection I will at first call the reader's
attention to the fact that, in batrachia, deprived of the medulla
oblongata, and exposed to the action of a low temperature, the
heart beating, on an average, 35 times in a minute and life
lasting four months — i. e. 172,800 minutes, it follows that, during
that time, the heart has more than 6,000,000 pulsations. In
summer, the maximum duration of life having been six hours —
i. e. 360 minutes, and the heart beating, on an average, 45 times
in a minute, it results that, during that life, the heart has only
1,600 pulsations — a number which is to the other as 1 is to 375.

This comparison shows how incorrect it is to suppose that in
consequence of the diminution of the vital phenomena in cold wea-
ther, a batrachian that lives several months does not live more
than another living only several hours in summer.

This opinion is also proved erroneous by the facts which I have
already related, and which show that all the functions and vital
properties existing in frogs deprived of their medulla oblongata,
appear to be as active as in unmutilated frogs. No doubt that
there is a notable difference between summer and winter as to the
activity of vital phenomena in frogs, but if we suppose that these
phenomena are in winter only the tenth of what they are in
summer, and if we consider, consequently, the duration of life in
winter as being only the tenth of what it is, we shall have,
nevertheless, a duration in winter forty or fifty times as great as
the duration in summer.

V. Now I have to examine why, in summer, the life of cold-
blooded vertebrata, deprived of the medulla oblongata, is much
shorter than in winter.

The principal cause of this difference is in the fact that the
cutaneous respiration, (it is known that the pulmonary respira-
tion does not exist in animals deprived of the medulla oblon-
gata,) which is sufficient as long as the temperature is very low,
becomes more and more insufficient, when the temperature be-
comes more and more elevated. So that the same law exists for
the cold-blooded vertebrata deprived of their medulla oblongata,
and for those which are not mutilated. The following experi-
ments concur to demonstrate the correctness of this view :

I have found that frogs deprived of their medulla oblongata
live much longer when placed in oxygen than in atmospheric air.
I have made two series of experiments — one in June, 1847, the
other in July, 1850. In both series the frogs were put imme-
diately after the operation, under a receiver full of oxygen. They
lived from eight to fourteen days at a temperature at which
life, in atmospheric air, is always shorter than six hours. The
temperature was from 64* to 84° F. (18° to 29° Cs.) These
frogs would have lived longer if the quantity of oxygen had
been more considerable.

By pulmonary insufflation I have maintained life in tortoises
deprived of the medulla oblongata, much longer than when in-

sufflation is not used. The duration of life was 7, 12, 13
and 17 days in four insufflated tortoises. When death occurred
in these four animals, they had been left without insufflation
more than five or six hours, and very likely they would have
lived longer had they been insufflated more frequently. In
four non-insufflated tortoises life lasted 3, 7, 19 and 23 hours.
These comparative experiments were made in summer in a tem-
perature varying from 64° to 86° F. (18° to 30° Cs.) The in-
sufflated tortoises lived longer in summer than non-insufflated
tortoises in winter.

From all these facts it is evident that in animals deprived of
the medulla oblongata, death is principally caused by insuffi-
ciency of respiration.

XVII ON THE INFLUENCE OF THE TEMPERATURE OF A WARM-
BLOODED ANIMAL UPON THE DURATION OF ITS LIFE WHEN IT
IS ASPHYXIATED.

One of the most positive facts in physiology is that every
animal needs oxygen in order to live. But if there is a com-
plete uniformity as to the necessity of oxygen for all animals,
there is also the greatest variety between the different species as
to the quantity of that gas which is necessary for the mainte-
ance of life. Very probably a great part of the physiological
differences between different animals, comes from the difference
in the quantity of oxygen absorbed by their blood in a given
time. The most important cause of the differences existing be-
tween cold and warm-blooded animals, and between young and
adult animals, is to be found in the differences in the quantity
of oxygen they absorb.

It is very remarkable that one of the principal laws relative
to the anatomical differences existing between the different spe-
cies of animals, appears to be also a law regulating their phy-
siological differences. In an anatomical point of view, a mam-
mal, at the different periods of its development, presents
alternately the forms of many different beings. In a physiolo-
gical point of view, a corresponding transformation occurs for
the mammals. They exhibit alternately the same phenomena
of life exhibited by many other different animals. For instance,
before its birth, the mode of breathing of a mammal is the

same as that of fishes. The oxygen absorbed by fishes exists
in a liquid ; the oxygen absorbed by the mammal foetus exists
also in a liquid, which is the blood of the mother. In fishes
and also in mammal foetuses, oxygen has to pass through many
membranes : in fishes, through the mucous membrane of the
bronchia and the membrane of the capillary vessels'; in the
mammal foetuses, through the membranes of the capillary vessels
of the maternal and the foetal placentas, and their mucous
coverings. After birth young mammals have an insufficient
power of breathing, and in this they are like the reptilia. They
are unable to absorb a sufficient quantity of oxygen to resist
the influence of cold ; and their power of retaining life when
deprived of oxygen, is comparable to that of the reptilia.

This fact -has been well established by the experiments of
Buffon, Boyle, Ens, Roose, Haller, Fontana, Legallois, and
more particularly W. F. Edwards. Nevertheless, these eminent
experimenters have left many important questions without so-
lution, some of which I will examine here.

In order to study the influence of temperature on the duration
of life in asphyxiated animals, W. F, Edwards dipped into
water, at different degrees of temperature, many animals of
different ages. Unhappily he did not take notice of the tem-
perature of the animals on which he experimented ; and we
will show that this circumstance is very important, because the
degree of that temperature at the instant when asphyxia begins,
has a considerable influence on the duration of life. Conse-
quently, to discover with exactitude the influence of the tempera-
ture of a medium, on animals deprived of breathing, it was
necessary to operate on animals at the same temperature. This
has been done neither by Edwards nor by any other physiologist.

A. priori it is easy to acknowledge that the duration of life
in animals asphyxiated can be influenced by four capital circum-
stances : 1st. The degree of the temperature of the animals ;
2d. The degree of the temperature of the medium ; 3d. The
age of the animals ; 4th. Their species.

Consequently four series of experiments were to be performed.
I have made them, and I propose to give here some of the results
I have obtained. The remaining shall be detailed in a special
paper.

I. Influence of the Temperature of young warm-blooded animals

on the length of their resistance to Asphyxia.
Experiment 1. Nine rabbits of the same brood and aged
about two days, were dipped into water at 25° Cent. (77° Fahr.)
Two of these animals, No. 1 and No. 2, had the temperature
which they generally have when they are in their nest covered
by their mother. The others had been cooled by having been
exposed to the action of an atmosphere at 10° Cent. (50° Fahr.)
No. 3 and No. 4 had been exposed for a quarter of an hour ;
No. 5 and No. 6 for three quarters of an hour ; and No. 7, No.
8 and No. 9 for an hour and a half. The results are represented
in the following table :

TABLE I.*

Mean
Nos. Temperature of Animals. Duration of Life- Duration of Life-

1, 35° to 36° Cent. (95 to 97° Fahr.) 10' 1

2, ditto ditto 14' j

3, 29° to 30° Cent. (84° to 86° Fahr. 16' 1

4, ditto ditto 21' j

5, 23° to 24° Cent. (74° to 75° Fahr.) 20' 1

6, ditto ditto j

7, 18° to 19° Cent. (65° to 66° Fahr.) 22' ^)

8, ditto ditto 29' I 28'

9, ditto ditto 33' j

The one that lived shortest (10',) was nearly at 36° Cent.
(97° Fahr. ;) the one that lived the longest (33',) was nearly at
18° Cent. (65° Fahr.) The difference of temperature being
17° or 18° Cent, (about 32° Fahr.) the difference as to the
duration of life was 23 minutes — that is, nearly two minutes
for each diminution of three degrees Fahr.

The same experiment performed on many breeds of rabbits,
has always given very nearly the same results.

These experiments prove that the temperature of young rab-
bits has a decided influence upon the duration of their life,
when they are deprived of breathing. I have ascertained that
the same thing takes place in cats, dogs, mice, and many species
of birds.

Experiment 2. I dipped into water at the temperature of 25°
Cent. (77° Fahr.) three bull-dogs.

* The existence of reflex movements has been used in this experiment
and in all the others as the proof of life.

TABLE II.
NOB. Temperature of Animals. Duration of Life.

1, . 38° Cent, (about 101° Fahr.) . 15'

2, . 30 " 86 " . 24'

3, . 22 " 77 " . 47'

Between No. 1 and No. 3 the difference of temperature was
16° Cent. (29° Fahr. ;) the difference in the duration of life was
thirty-two minutes — that is, two minutes for each diminution of
one centigrade degree (nearly 2° Fahr.)

Experiment 3. I put a ligature around the trachea of four
cur-dogs of the same brood, and aged three days.

TABLE III.
Nos. Temperature of Animals. Duration of Life.

1, . 37° Cent, (about 999 Fahr.) , 13'

2, . 28 " 83 " . 19'

3, . 24 " 76 " . 31'

4, . 19 " 67 t: . 51'

So that between the two extremes the difference as the dura-
tion of life, was 38 for 18 Cent, (about 32° Fahr.)

Many other experiments on very young dogs gave very nearly
the same results.

Experiment 4. On five cats, of the same brood, and aged two
days, I put a ligature around the trachea, after having cooled
three of them.

TABLE IV.

Temperature of the animals. Duration Mean

NOB. of life. duration.

1, 36° Cents., (about 97° Fahr.) 21' \ ,

2, 36 « « 97 « 30 f

3, 23 to 24 Cent., (74 to 76 Fahr.) 47 1 ''

4, 22 to 23 Cent., (72 to 75 Fahr.) 50 j 2 ,

5, 17 Cent., (about 63 Fahr.) 53
The temperature of the air air was then at 18 1° Cents., (65 Fahr.)

Experiment 5. On four mice, probably aged from three to
eight days, I put a ligature around the trachea after having
cooled three of them.

TABLE V.

NOB. Temperature of the animals. Duration of life.

1, 34° Cents., (about 94° Fahr.) 11'

2, 27 " « 81 « ' 14

3, 22 « " 72 « 10

4, 18 " « 65 « 14

I have obtained analogous results in experimenting on birds.

Experiment 6. On seven magpies, aged from four to eight
days, I put a ligature around the trachea, and opened widely
the thoraco-abdominal cavity.

Nos.
1,

2.
3,
4,

5,
6,
7,
8,
9,
10,

11,

TABLE IV.
Temperature of the animals.

36° Cent., (about 97° Fahr.

36
32
31*

26
26

22
20
20
18
10

97
97
90
79

79
72
68
68
65
65

Duration
of life.

20' £

28 $

26
39
12

103

Mean
duration.

24 '

72
76

Experiment 7. On other magpies I made the same experi-
ment, but without opening the thoraco-abdominal cavity, so that
asphyxia was much more complete.

TABLE VII.
Nos. Temperature of the animals. Duration of life.

1, 35° Cent., (95° Fahr.) 8'

2, 30 « 86 « 15

3, 24 « 76 « 27

4, 19 « 67 « 39

I have obtained nearly the same results from experiments
upon many sparrow-hawks, ravens and jays.

All these facts show how considerable is the influence of the
temperature of certain young animals and birds on the duration
of their life when they are asphyxiated.

II. Differences in the length of the resistance to asphyxia ac-
cording to the species of animals.

In order to discover what is the influence of the species, I made
the following experiment. I tied the trachea on twenty-two ani-
mals belonging to eleven species, all of which were aged about
four or five days. Their temperature had been cooled and they
were all at about 26° Cent., (79° Fahr.) The temperature of
the air was 19° Cent. (67° Fahr.)

Nos.
1,

9,
10,
11,
12,
13,
14,
15,
16,
IT,
18,
19,
20,
21,
22,

TABLE VIII.

Species. Duration of life.

Rabbit . . 18')
do. . : 24 $ '
Guinea pig , 6 )
do. . 9 ( '

Mouse
do.
Dog
do.
Cat

. 20 f

. 27 ; •

. 25 >
39 5
31 £

do.

36 5 *

Sparrow
do.

8 £
12 5 '

Pigeon
do.

5 }
9 S '

Jay
do.

13 £
17 5 '

Raven

14 >

do.

23 $ '

Sparrow Hawks 16 )
do. . 24 £ *

Mag-pie . 18 }
do. . 25 S '

Mean duration of life.

21'

22$

Now if we compare birds to mammals, we see that generally
mammals resist asphyxia more than birds. The two following
tables show the difference :

TABLE IX.
Mammals.

Guinea-pigs .
Rabbits

Mice

Cats

III.

Average

7*'

23£
32
334

TABLE X.
Birds.

Pigeons

Sparrows . ,. !,.

Jays

Raven

Sparrow Hawks .

Mag-pies ; /

Average

18|

—
15-J

Influence of the temperature of adult warm-blooded animals
on the duration of life when they are asphyxiated.

I have discovered that the degree of the temperature of adult
non-hybernating vertebrata has also a great influence on their

power of resisting asphyxia. Dogs, cats, rabbits, guinea-pigs
and birds, are subject to the same law when they are adult as
when they are very young. The lower their temperature, the
longer they live when they are asphyxiated. But although the
existence of this law for adult vertebrata is beyond all doubt, it
is sometimes very difficult to ascertain that existence. It is not
easy to diminish the temperature of a non-hybernating adult
mammal, or that of a bird, without exhausting the nervous and
the muscular power of the animal, and also without producing a
general and considerable perturbation. The action of a cold
bath, for instance, so powerfully excites the vertebrata, that
sometimes violent convulsions take place, and then death may
occur in a short time, even before the animal has lost 10° cent.
(18° Fahr.) of its temperature. However, some individuals may
be cooled without being exhausted by convulsions. I have ex-
perimented on a great many which were in this condition.
For more than eight years, without intending to make experi-
ments on this subject, I have had the opportunity of stating, on
more than a hundred adult rabbits or guinea-pigs, used for other
researches, that, when their temperature is diminished, the dura-
tion of their life, when they are completely deprived of breathing,
is decidedly longer than in the normal state. Whatever has been
the cause of the cooling, the effect has been the same. In these
numerous experiments, the animal heat has been diminished,
either by a disease, by a poison, by an injury in the nervous
centres, by the immersion of the animal in melted ice, or by the
application of a layer of oil, essence, or gelatine, to the whole
skin of the animal.

The best mode of cooling a non-hybernating warm-blooded
animal is to make the following experiment, in a room where the
temperature of the air is not far from freezing point. I remove
the superior part of the cranium of a mammal or of a bird, and
afterwards cut the brain, slice by slice, from the anterior to the
posterior extremity. After the ablation of the cerebrum and the
cerebellum, the animal is put on the floor, where it is left per-
fectly quiet for an hour or two. If the experiment is made on
a rabbit or a guinea-pig, the temperature of the animal then falls
from 40° Cent. (104° Fahr.) to 30° or 35° Cent. (86 or 95° F.)

A ligature being put around the trachea, I find that the animal
is then able to live generally from six to 8 or 12 minutes.

The more the animal heat is diminished, the more, in general,
is the resistance to asphyxia^ except in cases where cooling has
been produced too quickly.

On four adult rabbits, I put a ligature around the trachea,
and have obtained the following results :

TABLE XI. ^
NOB. Temperature of the animals. Duration of life.

1, 391° Cents., (103° Fahr.) 3£'

2, 35 « 95 « 6

3, 30| (between 86 and 87 Fahr.) 10

4, 25 Cents., (77 Fahr.) 14

On three guinea-pigs I put a ligature around the trachea, and
found the following facts :

TABLE XII.
NOB. Temperature of the animals. Duration of life.

1, 40° Cents., (104° Fahr.) 2f '

2, 35 « '95 « 5|

3, 30 « 86 « 12

The longest persistence of life, after the cessation of breathing
which I have found in adult non-hybernating animals, has been
in a cat aged five months, and whose temperature had been di-
minished to 19° Cent, (about 67° Fahr.) in consequence of the
laying bare of the abdominal viscera, and of the ablation of the
cerebrum by small parts.

I will say only a few words about my experiments on adult
birds.

Two pigeons were dipped into melting ice. In one of them,
whose temperature had fallen from 42° Cent. (108° Fahr.) to
35° Cent. (95° Fahr.) life lasted six minutes after the ligature of
the trachea. In the other, life lasted nine minutes ; its tempe-
rature had fallen from 42° Cent. (108° Fahr.) to 30° Cent.
(86° Fahr.)

I have obtained nearly the same results in experimenting on
fowls and on ducks.

Physicians are generally astonished at seeing that men at-
tacked with cholera are able to live almost without breathing.
My experiments show that the principal, if not the only cause

of the power living with so deficient a respiration, is the diminu-
tion of temperature. The same thing occurs in the last hour of
life in many cases of diseases, and particularly those of the
brain, of the respiratory organs, and in that dreadful disease of
children called scleroma.

It is easy to understand how a considerable breathing becomes
less and less necessary when the temperature of the animals
under experiment is diminishing.

Whatever may be the function of oxygen, it is positive that
most of the chemical changes which take place in the living ani-
mals are accompanied with a consumption of oxygen. If so,
when these chemical changes are diminished, the consumption of
oxygen ought to diminish. Now, as every diminution of the
temperature of an animal produces a proportionate diminution in
nearly all the acts of organic and animal life, and as these acts
are all accompanied by chemical changes in which oxygen is
consumed, it follows that, when they diminish, the consumption of
oxygen also diminishes.

In the act of running, or in a rapid walk, we consume much
more oxygen than in a state of rest. What we call rest is merely
a state of diminished activity; and when the temperature of a
mammal has been cooled down, the activity of most of the func-
tions is much more diminished than in the most complete rest. It
results from this fact, that when a warm blooded animal has lost a
notable part of its ordinary warmth, its consumption of oxygen
is much less than in a state of rest.

If the ligature of the trachea is made simultaneously on two
adult mammals of the same species, one of them being at its nor-
mal temperature, and the other at a temperature of 5° Cent.
(9° Fahr.) lower, we observe that this last one lives six, seven or
eight minutes, and the other from one and a half to three
minutes. If we suppose the quantity of oxygen existing in the
lungs and in the blood of these two animals is precisely alike in
both ; and if we admit that death occurs in asphyxia, either from
want of oxygen or by an action of carbonic acid, in both cases
these two animals ought to live a different length of time, because
the consumption of oxygen contained in blood and the produc-
tion of carbonic acid are quicker in one of them than in the
other. This explanation is so true, that when movements are

excited in the cooled animal, after the beginning of asphyxia, it
dies sooner than when it remains in rest.

From the facts and reasonings which are related in this note
I draw the following conclusions :

1st. The temperature of newly-born warm-blooded animals
has a great influence on the duration of their life when they are
asphyxiated.

2d. There are very considerable differences in the duration of
life in asphyxiated animals of different species, even when the
experiment is performed in the same medium, and while their
temperature is at the same degree.

3. The degree of the temperature of adult warm-blooded ani-
mals has also a great influence on the duration of their life when
they are asphyxiated.

4th. The influence of the animation of the temperature of a
warm-blooded animal on the duration of its life in asphyxia,
explains the persistence of life in man, in cases of cholera,
scleroma, and of some other diseases, when respiration is much
diminished.

XVIII ON THE CENTRAL SEAT OF GENERAL AND OP TACTILE

SENSIBILITY, AND ON THE VALUE OF CRIES AS MANIFESTA-
TIONS OF PAIN.*

To determine where is the seat of perception and of volition is
one of the greatest physiological questions. Flourens maintains
that this seat is in the central lobes. Many physiologists, among
whom are Bouillaud, Gerdy and Longet, have published papers
against the doctrine of Flourens. Their only important argu-
ment is that mammals deprived of their whole encephalon, ex-
cept the medulla oblongata and the pons varolii, continue to
possess the faculty of perceiving sensations, and that the percep-
tion of pain is then manifested by cries and agitation. When
the encephalon, says Longet,f is so much mutilated, in rabbits
and dogs, that only the pons varolii and the medulla ob-
longata remain, in the cranial cavity, these animals, although
they seem to be in a deep coma, are still able to agitate them-
selves, and to cry plaintively, under the influence of strong
external irritations ; but if a sufficiently deep alteration is made

* See Compfes Rendus de 1'Acad. des Sciences, 1849. t. xxix. p. 672.
f Traite de Physiol. Paris. 1850. t. ii, B. p. 38.

in the pons varolii there is an immediate cessation of the 'cries
and of the agitation ; it merely remains an animal in whom the
circulation, the respiration and the other nutritive functions
are momentarily accomplished.

On cats, rabbits and guinea-pigs, I have obtained a completely
different result in performing that experiment. After I had re-
moved, slice after slice, and from forwards backwards, the whole
encephalon, except only the medulla oblongata, I have found
that the mutilated animal, not only is much agitated, but cries
plaintively when it is pinched. If the medulla oblongata is also
removed, the cries cease, but the agitation still continues.

According to these experiments, it is evident that the pons
varolii is not the only seat of sensibility, the centre of perception
of tactile impressions, as Longet calls it, and that either the
medulla oblongata is the seat of general sensibility or the cries
do not prove that there is a perception.

Longet considers that the pons varolii is not only the centre of
perception for sensation of pain, but also for tactile impressions.
As to the tactile sensations he does not give the slightest appear-
ance of proof. Certainly neither the cries nor the agitation are
sufficient to authorize the opinion that the animal has felt a sen-
sation of tact. If the existence of cries could prove that there
is a perception of a tactile sensation, I should have to conclude
from my experiments that the medulla oblongata is the seat of
the faculty of perception of tactile sensations, for there are cries
after the removal of the whole encephalon except the medulla ob-
longata, and there are no more after the removal of this last
organ. If, instead of drawing conclusions from the existence of
cries, we take notice only of the agitation, we are bound to
conclude that the spinal cord is the seat of the faculty of percep-
tion of tactile sensations, for after this organ has been separated
from the medulla oblongata, agitation takes place when a limb is
pinched.*

Cries and agitation may be attributed to a property of the
nervous centres, which is completely different from the faculty of
perception of painful or tactile sensations. That property is the
reflex faculty of the true spinal marrow ;f it is the property of

* This conclusion is maintained as true by Senac, Caldarii, Kay, Legallois,
Paton, J. W. Arnold and many others,
f As Dr. Marshall Hall calls it.

uniting, in co-ordinate movements isolated muscular contractions,*
which is called by German physiologists the faculty of adaptation
to an end. That property manifests itself by movements similar to
those executed by unmutilated animals when they feel a pain ;
and it happens, sometimes, that these reflex movements are less
disordered than the movements consecutive to a violent pain in
an unmutilated animal. The agitation of the animals deprived of
all the parts of their encephalon is merely the result of an action
of the reflex faculty.

The cries also appear to exist only in consequence of a re-
flex action. This appears to be diflicult to be proved, and it will
seem nearly impossible to admit that cries may be produced
by an animal that has felt no pain, or that has not had the will
of crying. We may consider a cry as a noise produced in
the larynx, as many times a quick expiration is performed when
the vocal cords are stretched. Now as the tension of these cords
and the expiration is produced by muscular contractions, it is
easy to understand that these contractions are produced by a
reflex action as well as the contractions of the muscles of the
limbs.

For those who know that hiccup, coughing, sneezing, vomiting
and so forth, frequently are mere reflex phenomena, there ought
to be no difficulty in admitting that crying is a pure reflex
action.

If we here use the expressive language of Flourens, we will
say, that the medulla oblongata has the faculty of uniting in a
co-ordinate movement, the contractions of the expiratory muscles
and that of the tensor muscles of the glottis.

From the facts and reasonings contained in this note I will
now draw the following conclusions :

1st, That the experiment by which many physiologists have
endeavored to prove that the cerebral lobes are not the exclusive
seat of the perceptions, do not give such a proof.

2d, That animals can cry after the removal of the whole
encephalon, except only the medulla oblongata.

3d, That the existence of cries cannot prove that there is
a perception of pain, because cries result from muscular contrac-
tions which may be pure reflex actions.

* That is the name given by Flourens more than 25 years ago.

4th, That there is no proof that the pons varolii is the centre
of perceptions either of touch or of pain.

5th, That if it is admitted that cries prove that there is a
perception of pain, we should have to admit that the medulla
oblongata is also a centre for these perceptions.

XIX ON THE MODE OF ACTION OF SOME OF THE MOST ACTIVE

POISONS UPON THE NERVOUS SYSTEM.

Some of the results of my experiments on this subject have
already been published in the inaugural dissertation of my
learned friend and pupil, Dr. F. W. Bonnefin, with whom I per-
formed most of these experiments.*

I intend to give here only the results of my researches on the
poisons which produce convulsions. For the sake of brevity I
have called them convulsing poisons. The most important
among them are : strychnine, brucine, picrotoxine, morphine,
digitaline, cyanhydric acid, nicotine, cyanide of mercury, sul-
phide of carbon, chloride of barium, and oxalic acid.

The principal questions which I have endeavored to solve are
the following :

1. What is the part of the animal frame upon which these
poisons act in producing convulsions ?

2. By what mode of action do they produce convulsions ?
The parts of the body on which they could act are : —

a. The nervous centres.

b. The motor or centrifugal nerves.

c. The sensitive or centripetal nerves.

d. The muscles.

Of course, the convulsing poisons could act upon these four
parts together, or upon two or three of them.

Now, as to the mode of action, these poisons could produce
convulsions directly or indirectly.

In other words these poisons might act : — 1. As excitants
either of the muscles or of the nervous system, and this is what
I call a direct action. 2. As causes of increase of the vital
powers of the muscles or of the nervous system, so that even a
slight excitation of these parts is able to produce convulsions,
and this is what I call an indirect action.

* Rech. Experim. sur Faction convulsivante des priucipaux Poisons, in 4
Paris, 1851.

The convulsing poisons do not appear to excite the muscles
or any part of the nervous system, and consequently they do not
act directly. They act merely in increasing the vital powers of
the nervous system, so that a slight excitation of the skin or ano-
ther part where there exist nerves of sensation is sufficient to pro-
duce convulsions. Therefore these poisons act indirectly in the pro-
duction of convulsions. They do not produce convulsions, they
merely act upon the nervous system, so as to render it capable of
producing convulsions when it receives an excitation. They do
not excite the nervous system, and their mode of action is altoge-
ther different from that of the mechanical, physical, and chemical
excitations which directly produce convulsions, when they are
applied to the medulla oblongata, or to the spinal cord.

This mode of action was already known as regards strych-
nine. Long ago Mr. Magendie* found that animals poisoned
by nux vomica, frequently remain without convulsions as long as
they are left without excitation, but that fits are immediately
produced when they are touched. Since that time Stannius,j-
Van Deen,{ Pickford,|| J. W. Arnold,§ Meyer, of Zurich,!! Mar-
shall Hall,** and A. Barnard, ff have observed many facts
proving that strychnine does not directly produce convulsions.
The following experiment, which I performed with the assistance
of Dr. Bonnefin, is still more demonstrative.

I introduce a large dose of strychnine into the stomach of a frog,
after the removal of its brain and of its medulla oblongata. As
the voluntary and the respiratory movements are then impossi-
ble, there is no spontaneous movement at all, and if the animal
is left perfectly quiet there are no convulsions. But as soon as
it is excited, even by the slightest touch, tetanus occurs.

In this case, it is evident that the convulsive fit is merely a re-

* Rxamen de I'action de quelques vegetaux sur la Moelle epiniere. Paris
1809, p. 7.

t Mueller's Archiv. 1837, p. 223.

jTraites et deeouvertes sur la Moelle epiniere, 1841. p. 123,
|| In Rorer und lTrar(|erlich'8 Vieiteljaheschrift. Bil. 2. 1843; p. 430.
§ Ueberdie verrichtunsj der VVerzeln der Ruckenmarksnerven, 1844.
T Schmidt's Jahrbuc-her, 1847, No. 8.

** Comptes rendusde 1'Acad. des Sciences, 1847, vol.24, p. 1054.
ff Proces verbaux de la Societe Philoinatique, 1847; p. 71.

flex act. But why is there a tetanic contraction instead of the
regular reflex movements ? The reason is that the reflex faculty
is considerably increased. This will be proved in a moment.

Before giving this demonstration, I must examine if there is
not also an increase in the vital powers of the muscles and of the
motor nerves. There was no reason to reject the supposition that
the convulsing poisons were capable of increasing simultaneously
the vital powers of the nervous centres, of the nerves, and of the
muscles. Consequently, I was led to perform the following
experiments, which prove : — 1st, that these poisons do not
increase the vital powers of the motor nerves and of muscles ;
2d, that they do not act as direct excitants upon these organs.

On young cats, on birds, and on reptiles, I removed the whole
portion of the spinal cord which supplies nerves to the posterior
limbs. A few minutes after, I injected into the rectum a
solution of a salt of strychnine. Convulsions occurred only in
the anterior parts of the body, and when I excited either the
motor nerves or the muscles of the posterior limbs, contrac-
tions were produced exactly as in animals not poisoned, but
there was no appearance of convulsions.

When the poison was placed directly on muscles or on
nerves, or when it was injected with blood in a limb separated
from the body, there was no appearance either of an exci-
tation, or of an increase in the excitability of the muscles, or of
the mDtor nerves.

The experiments of Magendie, of Emmert,* and of Backer,f
have demonstrated that after a transverse section of the spinal
cord, between its two enlargements, convulsions may be produced
in the palsied limbs, when the animal is poisoned with strychnine.
All the physiologists who have performed this experiment have
found it perfectly exact. Nevertheless, J. W. Arnold, J maintains
that the action is much less considerable in the posterior limbs,
in that case, than when the spinal cord is uninjured and united
with the medulla oblongata, and he concludes that the poison

* Exper. de effectu venenorum veget. americ. in corpus animale, 1817.
"I" Commentatio ad questionem physio)., ab Acad. Rheno traject, anno
1828, propositam.

J Die lehre von der Reflex-function. Chap. ix. and x. 1842.

acts much more on the medulla oblongata than on the spinal
cord.

Sometimes, as Arnold says, it occurs that the action of strych-
nine, in mammalia and in amphibia, is not so powerful in the
palsied parts, after the section of the spinal cord, as in the
non-palsied limbs. As to mammalia, the reason of this difference
is the diminution in the quantity of blood received by the part
of the spinal marrow separated from the encephalon. As to
amphibia, it is easily seen that immediately after the section of
their spinal cord, the reflex faculty in the part separated from
the encephalon is very weak, and if, then, strychnine is given to
the animal, it does not act very strongly ; but if the poison is
given two or three hours after the section of the spinal cord,
then the reflex faculty is very powerful and the poison acts vio-
lently, and sometimes more than if the spinal cord was uninjured.
In birds, which, as I have discovered, have constantly a power-
ful reflex faculty after the section of the spinal cord, strychnine
acts very energetically.

Lately, Stannius and Cl. Bernard have supposed that strych-
nine, instead of acting on the spinal marrow, acted on the nerves
of sensibility, and more particularly on their termination in the
skin. They base this hypothesis on some experiments, of which
only one is important. After the section of the spinal cord, at
the brachial enlargement, upon a frog, the animal is poisoned
with strychnine, and then convulsions occur nearly at each vo-
luntary or respiratory movement. But if the sensitive roots of
the spinal nerves are cut, the convulsions cease immediately.

Now, it is evident that this fact does not prove what Stannius
and Bernard have supposed ; because it may be explained as
well by admitting that convulsions are produced only in conse-
quence of an increase of the reflex faculty of the spinal cord,
as by the hypothesis of Stannius.

Van Deen * relates an experiment which is in opposition to
the theory of Stannius. If we take a frog prepared exactly as
in the experiment of this physiologist, we see that tetanus oc-
curs when the animal is thrown on the floor. In this case
tetanus is produced, although the sensitive roots are cut and
unable to act ; therefore tetanus is a consequence of an increased

* Loco cit. p. 123.

vitality in the spinal cord itself. But this experiment is not
decisive, because sometimes it occurs that such a mechanical
excitation in frogs, which have not been poisoned, produces
tetanus. Nevertheless I must say that the tetanus in this last
case is never so violent as in poisoned frogs.

A better experiment is to excite slightly with a needle, the
posterior columns of the spinal cord. Then, tetanus constantly
occurs in poisoned frogs, although the sensitive roots are divided,
and it very rarely occurs in frogs that are not poisoned.

I have already published* the following experiments, which
are much more decisive against the hypothesis of Stannius :

A ligature is put around the aorta of a frog, near its termi-
nation in the abdomen, and consequently the posterior limbs
cease to receive blood. Then the frog is poisoned with strych-
nine introduced into its mouth, and after a few minutes the
convulsive phenomena take place.

In this experiment the nerves of the posterior limbs do not
receive strychnine, whilst the spinal cord receives it ; therefore
convulsions are not produced ia consequence of an action of
strychnine on the sensitive nerves of the skin, as Stannius has
supposed, but in consequence of its action on the spinal cord.

Now, if we poison a frog after having divided the spinal cord
at the brachial enlargement, and after the section of all the
small arteries giving blood to the spinal column, we see that
convulsions do not take place in the posterior limbs, although
the reflex faculty is not lost in consequence of the cessation of
the circulation in the spinal cord, and that it remains for half an
hour or a little more in summer, and about two hours in winter.

In this experiment, blood containing strychnine reaches the
sensitive nerves of the posterior limbs, and not the spinal
cord, and there are no convulsions; therefore it is not on the
sensitive nerves that strychnine acts in order to produce con-
vulsions.

These two experiments are evidently decisive. In the first, we
see that when blood containing strychnine reaches the spinal
cord, and not the cutaneous nerves, there are convulsions ;
and in the second, we see that when blood containing strychnine
reaches the sensitive nerves and not- the spinal cord, there
* Gaz. Med. de Paris, 1849, p. 745.
6

are no convulsions. We must consequently draw from these ex-
periments these two conclusions :

1. Strychnine does not act upon the sensitive nerves.

2. Strychnine acts upon the spinal cord.

Now, from all the facts above related, two other conclusions
are to be drawn:

1. Strychnine does not excite the nervous system ; or, in other
words, strychnine does not produce convulsions directly.

2. Strychnine increases the reflex faculty of the spinal cord,
and so produces convulsions indirectly.

I do not intend to examine here whether strychnine kills in
producing convulsions, or by another action. Nevertheless, I
will say, that although convulsions are sufficient to kill in
asphyxiating, death, in cases of poisoning by strychnine, may
be also produced by another action of that poison. I have seen
animals in which convulsions did not take place at all, and
which have been killed by strychnine.

The other convulsing poisons that I have studied, appear to
act as strychnine, as to the production of convulsions.

The same experiments which I have related as regards
strychnine, have been performed with these poisons, and I have
obtained the same results. Sometimes, nevertheless, I found
some differences ; and, for instance, it appears that the chloride
of barium is a direct exciter of the muscular fibres, and cyan-
hydric and oxalic acids seem also to be slight but direct exciters
of the spinal cord.

The action of the chloride of barium is very important, be-
cause that poison is an exciter of the muscular fibres, and not of
the nerves. This fact proves that the muscular irritability may
be put in action without the intervention of the nerves.

The increase of the reflex faculty, by the convulsing poisons,
is a very important fact. How is that increase produced ? We
believe it takes place in consequence of an increase in the nutri-
tion of the nervous centres. J. Mueller* is of opinion that
there is no substance able to increase directly the vital proper-
ties of any organ. He says that nutrition alone is able to pro-
duce such an effect. I believe he is perfectly right, and I ad-
mit that the mode of action of the convulsing poisons, in the

* Manuel de Physiol., edited by Littre, 1851, t. i. p. 582.

production of convulsions, is merely to increase nutrition in the
nervous centres. It is important for practitioners to know that
mode of action. The usefulness of strychnine in many cases of
palsy, may be explained very easily by that action. I have
frequently seen, in the wards of the hospital la Charite at Paris,
paralytics under the care of Dr. Rayer, taking strychnine.
Every day the reflex faculty was increasing in them as long as
they took that substance ; and on the contrary, when the use of
that medicament was stopped, the reflex faculty began immediately
to dimmish, and in some patients it disappeared. If strychnine
was given anew, the reflex faculty was still increased. These
facts have been recorded with great care by my learned friend,
Mr. Chareot. I hope he will publish them.

From all the facts narrated in this paper, I believe I am enti-
tled to draw the following conclusions :

1. The convulsing poisons, more particularly strychnine,
brucine, picrotoxine, cyanhydric acid, nicotine, morphine, cyanide
of mercury, sulphide of carbon, digitaline, oxalic acid, appear
to produce convulsions, without acting either directly or indi-
rectly on the muscles or on the motor or sensitive nerves.

2. Generally these poisons do not appear to produce convul-
sions in acting directly on any part of the nervous centres.

3. These poisons, in producing convulsions, act only on the
parts of the nervous system endowed with the reflex faculty.

4. The mode of action of these poisons consists in the increase
of the nutrition of the nervous centres, by which excess of
nutrition the reflex faculty becomes much increased.

XX.— -ON THE CROSSED TRANSMISSION OF IMPRESSIONS IN THE
SPINAL CORD.

Numerous experiments which I have performed have proved
to the numerous physicians and students, who have seen
the most important of them, that the impressions made on one
side of the body are transmitted to the sensorium by the oppo-
site side of the spinal cord.

It is known that Galen* performed two experiments, which

* See : De locis affectis, lib. iii. cap. xiv ; or De anatomicis admonstra-
tionibus, lib. viii. sect. 6.

have been considered as demonstrating that there is no crossed
action in the spinal cord.

One of these experiments of Galen consisted in the transver-
sal section of a lateral half of the spinal marrow. After this
operation the animal was paralyzed in all the parts situated be.
hind the section, on the same side, so that the palsy was on the
right side of the body when the right side of the spinal cord was
divided, and vice versa.

The second experiment consisted in a longitudinal section on
the middle line of the spinal cord so as to separate into two late-
ral halves the part of that nervous centre supplying nerves to the
posterior limbs. After this operation the animal was able to
walk.

Galen, in these two experiments did not examine the state of
the sensibility. He speaks merely of the voluntary movements.
Nevertheless his researches were considered in this century as
completely proving that there is no crossing of action in the
spinal cord, either for sensibility or for voluntary movement.

The following experiments will prove that there is a crossing
of action for sensibility in that organ :

1st. If a lateral half (i. e. the posterior and the antero-lateral
columns and the gray matter of one side of the spinal cord), is
divided transversely at the level of the tenth costal vertebra, on
a mammal, it is soon evident that the sensibility is much dimin-
ished in the posterior limb opposite to the side of the sections.
On the contrary the sensibility instead of being lost appears
much increased in the posterior limb on the side where the sec-
tion has been made.

2d. If, instead of one transversal section of the spinal cord,
two, three, four or many more are made on the same lateral half
of that organ, the same results are obtained.

3d. If, instead of mere sections, a removal of a part of a
lateral half of the spinal cord, is effected, the same results are
still obtained. In performing this experiment a longitudinal
section, one inch in length, from behind forward, is made in the
median plane of the spinal marrow, and then two transversal sec-
tions on a lateral half are made at the extremities of the longi-
tudinal section, so that a part of the cord is completely separa-
ted from that organ and afterwards removed.

4th. If instead of dividing entirely a lateral half of the spi-
nal cord, a small part is left undivided towards the centre of
that organ, the posterior limb on the same side becomes much
more sensible, but the posterior limb on the opposite side remains
very sensible and sometimes it appears more sensible than in the
normal state.

5th. If in performing the section of a lateral half of the spi-
nal cord the instrument goes a little too far and divides also a
small portion of the other half, then the posterior limb on the
side of the complete section is less sensible than in the normal
state, and the posterior limb of the opposite side, loses com-
pletely its sensibility.

6th. If the section of a lateral half of the spinal cord is made
at the level of the second or third cervical vertebra, it is found
that the sensibility becomes very quickly much greater in the
parts of the body on the same side as the section, and on the
contrary the parts on the other side becomes evidently less sen-
sible.

7th. If after a section of a lateral half of the spinal cord at
the level of the eleventh costal vertebra, another section is per-
formed on the other side of that organ, at the level of the sixth
costal vertebra, so that the two lateral halves are divided, then
sensibility in most of the cases is lost, on both sides. Some-
times it retains a very slight degree of sensibility, more parti-
cularly in the posterior limb on the side where the spinal cord
has been divided at the level of the sixth costal vertebra.

8th. If two sections of lateral halves are made as in the pre-
ceding experiment, but at a greater distance, one from the other,
on the right side for instance at the level of the twelfth costal
vertebra, and on the left side in the cervical region, nearly the
same results are obtained as to the posterior limbs, but the sen-
sibility is increased in the right anterior limb and it remains very
evidently, but much diminished, in the left anterior limb.

9th. If a longitudinal section is made on the part of the
spinal cord giving nerves to the posterior extremity, so as to
divide that part into two lateral halves, then it is found that sen-
sibility is completely lost in the two posterior limbs, although
voluntary movements take place in them.

10th. If a similar separation of two lateral halves of the spi-

nal cord is made'on the whole part supplying nerves to the anterior
limbs, then it is found that sensibility is lost in both these limbs,
and that it is only slightly diminished in the posterior limbs.

llth. If the same operation is done as in the preceding expe-
riment, and afterwards if a transversal division is made on one
of the lateral halves, in the place where it is separated from the
other, then it is found that the posterior limb on the side of the
transversal section remains sensible, and that the other posterior
limb loses its sensibility.

These experiments prove very clearly that the sensitive ner-
vous fibres are crossed in the spinal cord. The 9th, 10th, and
llth, demonstrate directly the crossing. In these experiments
the crossed fibres are all cut, and sensibility is lost. This fact
appears to prove that all the sensitive fibres cross each other ;
but it will be easily understood that on account of the loss of
blood, and of the general diminution of sensibility produced by
the excessive pain of the operation, if there are some fibres
which remain without crossing, they are insufficient to give
sensations.

As to the experiments consisting in transversal sections of a
lateral half, they prove that sensibility is much diminished in the
side of the body opposite to that of the section ; consequently
they prove also that there is a crossing of a great part of the
sensitive fibres.

The fact that transmission of impressions made on one side of
the body takes place, at least for a great part, in the opposite
side of the spinal cord, is proved evidently by the eight first
experiments, but much more by the 7th and the 8th experiments
in which it is found that, after a section of a lateral half of the
spinal cord, sensibility remains on the same side, and that it is
nearly entirely lost after a second section of the other lateral
half in another place.

If most of the nervous sensitive fibres are crossed in the
spinal cord, then it is not exact to admit that the crossed paraly-
sis of sensibility in cases of diseases of the brain, is explained
by the crossing of fibres which exists in the pons Varolii and in
other parts of the encephalon. Many opinions have been pro-
posed as regards the place where the sensitive nervous fibres
make their crossing in the encephalon. According to some pa-

thologists, this crossing takes place all along the medulla oblon-
gata, the pons Varolii, tubercula quadrigemina and the crura
cerebri. In all these organs there is truly a crossing of fibres,
but we do not know what are these fibres. Ch. Bell believes
that the crossing of the sensitive fibres takes place in the poste-
rior surface of the medulla oblongata, in a great part of the
length of the fourth ventricle. Longet supposes that this cros-
sing exists at the anterior border of the pons Varolii, where the
two processi cerebelli ad testes cross each other.

My experiments prove that if there are some fibres coming
from the trunk and from the limbs which do not effect their
crossing in the spinal cord itself, their number ought to be very
small. Therefore the fibres which are found crossed in the ence-
phalon are not sensitive fibres coining from the limbs and from
the trunk, as all physiologists have supposed they were.

My experiments were made on many different species ;
guinea-pigs, dogs, cats, sheep, and rabbits. In all the same re-
sults were obtained.

To ascertain the degree of sensibility, I used various modes
of excitation ; mechanical, galvanic, physical, (i. e. warmth
and cold,) and chemical. I constantly compared the degrees
of sensibility in the parts of the body situated behind the in-
jured portion of the spinal cord, with the anterior parts of the
body, and particularly with the face. It is thus that I have been
able to ascertain the existence of an increase or of a diminution
in sensibility.

Sometimes I have given chloroform to animals having had a
lateral half of the spinal cord divided in the cervical region.
I have found that complete loss of sensibility appeared at
first in the parts of the body opposite to the section of the spinal
cord, the head and neck, and at last in the parts of the body be-
hind the section of the cord, on the same side. This experiment,
as well as'many others, prove undoubtedly that there is an increase
of sensibility in these last parts. I will try in another article to
explain this hyperaDSthesia.

I believe I am entitled to conclude from the facts above re-
lated :

1st. That most of the impressions made on one side of the
body are transmitted to the sensorium by the opposite side of

the spinal cord, so that the impressions on the left side of the
body are transmitted by the right side of the spinal cord, and
vice versa.

2d. That the assumed function of the crossing of fibres in the
pons Varolii, and the neighboring parts, does not belong to these
fibres, but to the fibres of the spinal cord, all along which they
cross each other.

XXI . — ON MUSCULAR IRRITABILITY IN PARALYZED LIMBS, AND ITS
SEMEIOLOGICAL VALUE.

Marshall Hall has published many papers, in which he has tried to
prove that the degree of muscular irritability in paralyzed parts maybe
used as a means of diagnosis between cerebral and spinal paralysis.

He calls cerebral paralysis that in which the paralyzed part is de-
prived of the action of the brain, but not entirely, or not in the least, of
the influence of the spinal cord. On the contrary, he calls spinal
paralysis that in which the palsied part is altogether deprived of
the action of both the brain and the spinal marrow. The cause
of the cerebral paralysis may be seated either in the encephalon or
the spinal cord; and the cause of the spinal paralysis may be seated
either in the spinal cord or in the nerves.

In the same individual these two kinds of paralysis may exist
together. Suppose a man in whom the brachial enlargement of
the spinal cord is considerably softened, and consequently unable
to act ; the upper limbs then have a spinal paralysis, and the
lower limbs, receiving their nerves from a healthy part of the spinal
cord, have only a cerebral paralysis.

According to Marshall Hall, the cerebral paralysis is attended by
augmented muscular irritability, and the spinal paralysis is attended
by diminished irritability. He bases this opinion on the following
experiments, and on some clinical observations.

On six frogs he divided the spinal marrow immediately below
the origin of the brachial nerves ; and he removed a portion of the
ischiatic nerve of the right posterior extremity. He had imme-
diately, or more remotely, the following interesting phenomena :

1st. The anterior extremities alone were moved spontaneously;
both posterior extremities remaining entirely motionless when the
animal, placed on its back, made ineffectual efforts to turn on the
abdomen.

2d. Although perfectly paralytic in regard to spontaneous motion,
the left posterior extremity, that still in connexion with the spinal
marrow, moved very energetically when stimulated by pinching the
toes with the forceps.

3d. The right posterior extremity, or that of which the ischiatic
neive was divided, was entirely paralytic, both in reference to spon-
taneous and excited motions.

4th. After the lapse of several weeks, whilst the muscular irri-
tability of the left posterior extremity was gradually augmented, that
of the right was gradually diminished, — phenomena observed when
the animal was placed in water through which a slight galvanic
shock was passed accurately in the direction of the mesial plane.

5th. Strychnine being now administered, the anterior extremities
and the left posterior extremity, or that still in connexion with the
spinal marrow, became affected with tetanus ; but the right poste-
rior extremity, or that severed from all nervous connexion with the
spinal marrow, remained perfectly placid.

6th. Lastly, the difference in the degree of irritability in the mus-
cular fibre of the two limbs was observed, when these were entirely
separated from the rest of the animal.

After this exposition of the results of his experiments, Marshall
Hall adds : ** In a word, the muscles of the limb paralyzed by its
separation from both cerebrum and spinal marrow, had lost their
irritability ; whilst those of the limb separated from its connexion
with the cerebrum only, but left in connexion with the spinal mar-
row, not only retained their irritability, but probably possessed it in
an augmented degree.*

It is easy to prove that Marshall Hall has been completely mis-
led by his experiments.

It is well known that the more a muscle is excited, the more it
contracts. As the degree of irritability is judged by the degree of
the contraction, it follows that to know what is the degree of mus-
cular irritability we ought to apply the same excitation to the mus-
cles we desire to compare. In his experiments with galvanism and
with strychnine, Marshall Hall has not done so. He has applied

* On the diseases and derangements of the nervous system. 1841, p.
215.

galvanism, so as to excite much more the muscles of the left side
united with the spinal cord, than those of the right side.

The muscles of the left side were excited :

1st. Directly by the galvanic current.

2d. In consequence of the excitation of the motor nerves.

3d. In consequence of the excitation of the spinal cord, directly
by the galvanic current, and secondarily in consequence of the
excitation of the sensitive nerves.

So that the muscles on that side were moved not only by the
direct excitation on them, but also by a reflex action, and in conse-
quence of the direct excitation of the spinal cord.

As to the muscles of the right side, they were only excited by
the small part of the galvanic current passing in them. During the
first, and perhaps the second and the third week after the section of
the ischiatic nerve, the muscles were also slightly excited by the
motor fibres of that nerve, but after that time these fibres had lost
their vital property, and were unable to excite a contraction in
muscles.

From this analysis it results clearly that the mode of comparison
of the two limbs, by the passage of a galvanic current, as it has
been employed by Marshall Hall, could not decide in which side
the muscles were more irritable.

The use of strychnine, also, could decide nothing in this ques-
tion, because, as I have proved in a former article, this poison is not
able to act upon muscles. It acts only on the nervous centres, and
especially on the spinal cord. Therefore, the production of tetanus
in one limb and not in the other, in the experiment of Marshall
Hall, proves nothing at all as to the degree of muscular irritability.

To know what is that degree, it is necessary to separate the two
limbs from the trunk, and then to excite directly the muscles. Mar-
shall Hall has made this experiment, but he says nothing about the
circumstances under which it was performed, and these circum-
stances were, as it will be shown, extremely important.

In my experiments, instead of dividing only the ischiatic nerve,
I divided the four nerves going to one of the posterior limbs, of
many frogs, in whom the spinal cord was divided immediately
behind the roots of the brachial nerves.

I have found on the separated limbs of these frogs :

1st. That, at first, the muscular irritability was greater in the
limb which had been deprived of the action of the spinal cord and
of the brain, than in the limb, deprived only of the action of the
brain.

2d. That, at a variable time after the operation, the irritability
was at the same degree in the two limbs.

3d. That, at last, the irritability became greater in the limb only
deprived of the action of the brain, than in the other.*

The differences in the degree of irritability have been
observed : 1st. By the degree of the contraction under the influence
of the same excitation; 2d. By the duration of irritability.

I have found that during a time, varying much according to sea-
sons, and to many other circumstances, the muscular irritability
increases in the two posterior limbs in a frog operated upon as I
have described, and that the increase was more considerable in the
limb where the nerves were divided than in the other.

If we compare two frogs, one operated on as before, and another
having only had a division of all the nerves on one of the pos-
terior limbs, we find, a few days after the operation, that in the
four limbs separated from the body there are great differences as
to the degree and the duration of muscular irritability : 1st. The
three paralized limbs have a greater irritability than the one not
at all paralyzed. From the three paralyzed limbs the two in
which the nerves have been divided have both the same degree
of irritability, and more than the limb in which there was only
what Marshall Hall calls a cerebral paralysis. 2d. The irrita-
bility has lasted longer in the two limbs in which the nerves had
been cut, than in the two other limbs.; and from these two, that
in which there was a cerebral paralysis has remained longer
irritable.

If we examine the irritability in the posterior limbs of two
frogs, operated on as aforesaid, for ten, twelve, or fifteen days,
then we find that it is nearly at the same degree in the three
paralyzed limbs, and greater there than in the non-paralyzed
limb.

* There is, in these experiments, a cause of error, arising from the
existence on one side, and the absence, or, at least, a diminution in the
other, of the vital power of the motor nerves ; but the difference is trifling
when the nerves are divided very near their entrance in the muscles.

If the comparison is made four or five weeks after the opera-
tion, then the non-paralyzed limb has a greater irritability than
the three paralyzed, and, from these three, the one deprived only
of the cerebral action has a greater irritability than the two
others.

The same experiments made on other animals than frogs, i. e.
on guinea-pigs and rabbits, have given like results. I shall pub-
lish the details of these last experiments in a special paper, in
which I intend to examine the value of the clinical observations
of Marshall Hall, R. B. Todd, Duchenne de Boulogne, and
others. I will merely state here, that in many cases it is almost
impossible to know what is the difference in the degree of mus-
cular irritability in a paralyzed limb, compared with a healthy
limb, in a living man or animal. Galvanism and strychnine can-
not give us any exact notion in this respect. I ought to add,
that if we could know what is the relative degree of irritability
in a paralyzed limb, we could not make use of that knowledge
for the diagnosis of the seat of the alteration producing the
paralysis. On the other side, we do not want to know what is
the degree of irritability in order to establish such a diagnosis.
It will be, almost constantly, easy to know whether a paralysis is
a cerebral or a spinal one. The existence of reflex actions in
the paralyzed parts, is sufficient to prove that there is a cerebral
paralysis, and the absence or the slight degree of these actions
will prove that there is a spinal paralysis.

The following conclusions may be drawn from the facts
above related, and from others that I have not yet published.

1st. The degree of muscular irritability in paralyzed parts,
becomes rapidly greater than in the healthy parts, but, after a
variable length of time, it diminishes, and, as it is well known,
it may disappear.

2d. The muscles deprived of the action of both the brain and
the spinal marrow, become rapidly more irritable than the mus-
cles deprived only of the action of the brain, but, after a certain
time, there is also in them a more rapid diminution of irritability
than in the others.

3d. It appears certain that the muscular irritability never

disappears completely in parts deprived only of the cerebral
action.*

4th. In certain cases of paralysis, and more particularly of
the face, as after the removal of a large part of the facial nerve,
the muscular irritability may exist for years, at least in rabbits
and other animals.

5th. It is very difficult, and sometimes almost impossible, to
know the relative degree of muscular irritability in healthy parts
compared with paralyzed parts, and such a knowledge could not
be of a great semeiological value.

6th. The existence or the absence of reflex actions as a means
of diagnosis between the cerebral and the spinal paralysis, has
a much greater value than the degree of muscular irrita-
bility.

XXII. — ON THE INCREASE OF ANIMAL HEAT AFTER INJURIES
OF THE NERVOUS SYSTEM.

In another part of this seriesf I have endeavored to prove
that the local increase of temperature following the section of
the sympathetic nerve, is the result of paralysis of the blood-
vessels. I will now relate some other cases in which a local
increase of temperature takes place after various other inju-
ries of the nervous system, and apparently in consequence of
the same cause.

It was known, long ago, that an injury to the nervous system
might be followed by a partial or even a general elevation of
animal heat. Sir B. Brodie says,! Mr. Chossat has published an
account of some experiments on animals, in which he found
that the division of the superior portion of the spinal cord
produced a remarkable evolution of animal heat, so that it was
raised much above the natural standard. I have made experi-

* I have had a pigeon on which nearly an inch of the costal part of the
spinal cord had been removed, and on which the muscular irritability in
the posterior limbs, and a very great reflex power, have existed as long as
I have taken care of it, i. e. more than twenty-seven months. I ought to
say that there has been no re-union of the separated parts of the spinal
cord.

•j- Medical Examiner, August 1853, p. 489.

JMedico-Chirurg. Transactions, 1837. Vol. xx., p. 132.

ments similar to those of Mr. Chossat, and have met with similar
results. I have also seen several cases in which an accidental
injury of the spinal cord has produced the same effect. The
most remarkable of them was that of a man who was admitted
into St. George's Hospital, in whom there was a forcible separa-
tion of the fifth and sixth cervical vertebroe, attended with an
effusion of blood within the theca vertebralis, and laceration of
the lower part of the cervical portion of the spinal cord. Res-
piration was performed by the diaphragm only, and, of course,
in a very imperfect manner. The patient died at the end of
twenty-two hours ; and, for some time previous to his death,
he breathed at very long intervals, the pulse being weak and
the countenance livid. At last there, were not more than five
or six inspirations in a minute. Nevertheless, when the ball
of a thermometer was placed between the scrotum and the
thigh, the mercury rose to 111° of Fahrenheit's scale.
Immediately after death, the temperature was examined in the
same manner, and found to be still the same.

Brodie was mistaken as regards the experiments of Chossat.
Instead of finding an increase in the animal heat after the sec-
tion of the inferior portion of the spinal cord, Chossat found
a considerable diminution in the temperature of dogs. But in
two cases, where the spinal cord was divided at about the
level of the last dorsal vertebra, in dogs, Chossat* found an
increase in the animal heat. In one of these experiments, the
increase was from 41°.l to 41°.5 Cents., (105°.98 to 106°.7
Fahr.) In the other, the increase was from 41°.l to 42°. 9
Cs., (105°.98 to 109°.6.)

Dr. Macartney! found an increase in the temperature of
parts paralyzed in consequence of the division of their nerve.
II. Nasse,J who made many experiments on this subject, some-
times observed an elevation in the temperature of the pa-
ralyzed parts after the division of the sciatic nerve, or after
the partial destruction of the spinal cord.

* Mem. sur P influence du eyst. nerv. sur la chal. anim. These de Paris.
No. 120.— 1820, p. 35. Exps. xxiii and xxiv.
•j- Treatise on Inflammation, 1838, p. 13.
j Yuterstirchungor zur Physiol. und Pathol., 1839, v. ii., p. 190.

In more than twenty experiments, I only once found an
increase in the temperature of the leg of a guinea-pig, after the
section of the sciatic nerve. This increase lasted about two
or three days after the operation, and it was of two degrees Fahr.

After a complete transversal section of the spinal cord in the
lumbar region, in birds and mammals, I found, repeatedly,
an increase of one, two or three degrees Fahr. in the temperature
of the paralyzed parts. I ascertained that it is not in conse-
quence of an increase of the general temperature of the animal
that such an increase exists. It is to be found only in the
paralyzed parts.

I never found any increase of temperature after a complete
transversal section of the spinal cord, either in the cervical or in
the dorsal region.

After a section of a lateral half of the spinal cord, at the
level of one of the three or four last dorsal vertebrae, I have
almost constantly found an increase in the temperature of
the posterior limb on the side of the section. The elevation
varied from one to four degrees Fahr. On the contrary, there
was a diminution of from one to five degrees Fabr. in the
temperature of the other leg. In some cases, in consequence of
the increase of temperature on one side and its diminution on
the other side, I found a difference of six or seven degrees
Fahr. in the temperature of the two limbs. It is very remark-
able that, together with the increase of temperature in one
limb, there is an augmentation of sensibility, and with the di-
minution of temperature in the other limb, there is also a dimi-
nution of sensibility.

Sinca the publication of the results of my experiments on the
sympathetic nerve, I have performed them many other times,
and I have found that the result is not so constant as Dr. A.
Barnard and myself had admitted. In some rabbits there was
no decided increase in the vascularization and in the tempe-
rature of the face. I ought to say that, in these cases, the two
ears were already warm, and very vascular before the operation.
I have found, also, that generally in very cold weather the ex-
tremity of the ear of rabbits, on the side of the section of the
sympathetic nerve, remains cold.

From my experiments and from the observations and experi-

ments of Brodie, Chossat, H. Nasse and Macartney, it results
that the following opinion of Dr. Cl. Bernard is incorrect. He
says : " It is known that injuries of the cerebro-spinal ner-
vous system constantly produce a total or a partial diminu-
tion in the temperature of animals, either when a nerve has been
divided or when the injury is made on the nervous centres."*
He says also that an injury of the sympathetic nerve produces
a very rapid increase of temperature ; so that the sympathetic
nerve and the cerebro-spinal nervous system are considered by
Dr. Bernard as completely different, one from the other, as to
the influence on animal heat when they are injured. The one
should increase and the other diminish animal heat.

The truth is that these two effects — increase and diminution —
may exist after an injury of either the sympathetic or the cere-
bro-spinal nervous system ;f and, in both cases, the increase may
exist, at first, and be followed by a diminution.

Before pointing out the co-existence of certain facts with the
increase or diminution of animal heat, I think it necessary to es-
tablish a distinction between the cases of increase of animal heat
after injuries of the nervous system.

In some cases (as those related by Brodie) there has been an
increase of temperature above the natural standard of animal
heat. These are very extraordinary and very rare cases, and
it is not my intention to attempt to explain them here. In the
cases, the degree of temperature, although increased in some other
paralyzed parts, has not been above the normal degree of blood
heat. This is the only kind of increase of animal heat that I
have observed, and this I will attempt to explain.

I have found that, — ceteris paribus, — the more the arteries
and capillaries are dilated, the higher is the degree of tempera-
ture. This law is proved by the following facts :

1st. In all the cases of paralysis (from whatever cause)
where I have found a diminution in the degree of temperature
of a paralyzed part, the arteries and capillaries were evidently
much contracted.

2d. In the cases where the temperature was normal, the blood-
vessels were of their natural size.

*Gaz. Medic, de Paris, Vol. 7, No. 14, p, 227.
t Vide : Chossat, loco clt.: pp. 41-46.

3d. In the cases where the temperature was increased, I have
constantly found the arteries and capillaries enlarged.

4th. In some cases, I have found the same changes occurring
in the temperature and in the blood-vessels. The temperature
at first was greater than usual and the blood-vessels dilated ;
afterwards both the temperature and blood-vessels became natu-
ral ; and, at last, the temperature becoming lower than usual,
the size of the blood-vessels became smaller.

I need not say that the changes occurring in paralyzed
parts in accordance with the size of the blood-vessels were the
results of the differences in the amount of blood passing in these
parts.

Now, it will be asked how, in certain cases of palsy, the size
of the blood-vessels is larger than usual, and smaller in other
cases. I .cannot explain how it is so, but I can assert that it is
a fact.

From the facts and reasonings related in this article, I draw
the following conclusions :

1st. An injury of the nervous system may produce in the
parts, which then become paralyzed, either an increase or dimi-
nution of temperature.

2d. The sympathetic nerve and the cerebro-spinal nervous
system appear not to be different one from the other, in this
respect.

3d. The degree of temperature of paralyzed parts depends on
the quantity of blood they receive ; and this quantity varies ac-
cording to the size of the arteries and capillaries of these parts.

4th. It is a fact, hitherto unexplained, that the arteries and
capillaries may be either dilated, normal, or contracted in para-
lyzed parts.

XXIII CAUSE OF THE STOPPING OF THE HEART'S MOVEMENTS,

PRODUCED BY AN EXCITATION OF THE MEDULLA OBLONGATA OR
THE PAR VAGUM.

E. II. and E. Weber have discovered a singular fact, hitherto
unexplained. When the par vagum or the medulla oblongata is
excited by a powerful electro-magnetic current, in a living
animal, the movements of the heart are suddenly stopped. This

should be what is known for all motor nerves and muscles, if the
cessation of the movements of the heart was the result of a per-
manent contraction. But the heart is not at all contracted, and,
on the contrary, it remains perfectly placid.

This is entirely different from what we know to be the case
for other muscles.

I have found that a violent mechanical excitation of the me-
dulla oblongata produces also the same stopping of the heart's
action.

Is the heart in a state of rest in consequence of a loss of its
irritability or of an interruption of the excitation necessary to
its action ? The following fact proves that this second opinion
is the right one. When the heart is stopped, every direct exci-
tation upon it produces some beatings, and then, its irritability
appears to be entire. The stopping, consequently, depends on
the absence of excitation.

The cause exciting the heart to beat is in the blood contained
in the capillaries of this organ, as I will try to prove in another
article. Now, if we suppose that the galvanization of the par
vagum produces a complete constriction of the capillaries of the
heart, it is easy to understand why the heart is stopped: it is
because the excitation cannot take place on account of the ex-
pulsion of the blood from the capillaries.

It will be asked on what ground we base the supposition that
the capillaries are so contracted that they prevent entirely, or
nearly so, the passage of the blood. I will answer :

1st. That it is known that a galvanization of certain nerves
(and I have discovered that it is so with the capillaries of the face
and ear when the sympathetic nerve is galvanized) may pro-
duce a considerable constriction of capillaries.

2d. That it is known that the nerves of the heart are distri-
buted much more to its blood-vessels than to its muscular tissue.

3d. That, by our supposition, we place the fact of the stopping of
the heart's movements among the well known facts, that an excita-
tion of a molar nerve produces a contraction of the muscles to
which it is distributed ; and, therefore, we are not obliged to admit
that an excitation of a nerve is able to produce directly either a
contraction of or the cessation of existing contractions.

There is a practical consequence to be drawn from the fact that

in the case of an excitation of the medulla oblongata, the stopping
of the heart is not produced by a loss of irritability of this organ.

Many cases of syncope are produced by a stopping of the
heart's movements in consequence of the influence of an emotion
on the medulla oblongata. In these cases it would be of
very great importance to excite directly the beatings of the heart,
either by compression of the chest or by an application of gal-
vanism.

We ought to say that galvanism applied directly to the heart
increases its beatings instead of diminishing them.

XXIV. — ON A SINGULAR DISTURBANCE IN THE VOLUNTARY MOVE-
MENTS, APPARENTLY PRODUCED BY AN ACTION OP ATMOSPHERIC
AIR ON THE GRAY MATTER OF THE SPINAL CORD, IN BIRDS.

Some years ago I discovered that after the removal of a large
quantity of the gray matter that exists in birds, on the posterior
surface of the spinal cord, in the lumbar region, a great disturb-
ance took place in the voluntary movements. I attributed this
disturbance to the loss of gray matter. I have found, three
or four months since, that the same disturbance existed in the
voluntary movements after I had merely laid bare the gray
matter, and immediately after it had been exposed to the action
of air.

I am perfectly satisfied that it is not in consequence of a
mechanical excitation of the spinal cord, accidentally produced
during the operation of the removal of the bones and membranes,
that this disorder takes place.

When the spinal cord is laid bare elsewhere than in the region
of the lumbar enlargement — that is, in any place where the white
substance covers completely the gray matter — there is no disturb-
ance produced in the voluntary movements.

That disturbance very much resembles the so-called titubn-
tion which exists after either the removal of the cerebellum or
the section of muscles of the posterior part of the neck. At
each movement of progression, the animal tends to fall either
forwards, backwards, or laterally. It does not fall completely,
but is obliged, in order to avoid falling, to make use of its wings,
its tail and its beak.

XXV. — ON THE TREATMENT OF EPILEPSY.

I have made numerous experiments with regard to the treatment
of this dreadful affection, and I intend to publish them, in extenso,
when some points that are still obscure have become clear to my
mind. Here I will merely relate some of the most important results
of my researches. As I have had the opportunity during the last
three or four years of observing every day a great many animals
(more than a hundred) which had a convulsive affection resembling
epilepsy very much, I have been able to discover some very in-
teresting facts, among which are the following :

1st. For each epileptic animal, the number of fits, in a given
time, is generally in a direct proportion with the quantity of food
taken.

2d. There is an inverse proportion between the amount of exer-
cise and the number of fits.

3d. Cauterisation of the mucous membrane of the larynx is
able either to cure or to relieve these epileptic animals.

The convulsive affection existing in almost all these animals
was the consequence of a transversal section of a lateral half of
the spinal cord, in the dorsal or in the lumbar region.

I have already published the results of my experiments on
epilepsy, in rny lectures before large classes of Physicians and
Medical students, both in France in 1851 and in this country in
1852.

These results are in perfect accordance with the views of Dr.
Marshall Hall in relation to epilepsy. As the views of this emi-
nent biologist are generally known, I need not expose them, and
I will merely remind my readers of the three following points :

1st. The first muscles that contract spasmodically in almost
all, if not in all, the cases of epileptic fits, are those of the larynx
and the neck : 2d, spasm of the glottis taking place then,
produces suffocation, in consequence of which convulsions are
produced in the trunk and the limbs; 3d, tracheotomy may pre-
vent these convulsions by preventing suffocation, and it is known
that in some cases tracheotomy has cured epilepsy.

It has been objected to Marshall Hall that in cases of poison-
ing by strychnine, convulsions take place even when a tracheal
tube renders respiration perfectly free. This objection has no

value, because the state of the spinal cord in epileptics is not
the same as in men or animals poisoned by strychnine. Cer-
tainly the excitability of the spinal cord is greater in epileptics
than in healthy persons, but the degree of excitability of that
nervous centre is much greater in persons poisoned by strych-
nine than in epileptics ; and, therefore, it is easy to understand
that certain excitations are able to produce general convulsions
in one case and not in the other.

If we give a very slight dose of strychnine to an animal, so as
not to poison it, but merely to increase slightly the excitability of
the spinal cord, there are no convulsions when we touch or
pinch or burn the skin, but if we prevent breathing for a few
seconds only, general convulsions take place, exactly as in epi-
leptic men or animals.

It has been said also, in opposition to Marshall Hall, that a
spasm of the glottis of the severest kind occurs in cases of hoop-
ing cough, of spasmodic croup and even of apoplexy, without the
occurrence of any other convulsions. The answer to this objec-
tion is, that in epilepsy the spinal cord is more excitable than in
these other diseases, so that the same kind of excitation does not
produce the same effects.

A great many facts, that I will publish elsewhere, prove that
black blood, very probably by its carbonic acid, is an excitant of
the spinal cord and of the medulla oblongata. When, as is
the case in asphyxia, the blood is not oxygenated and deprived of
the carbonic acid constantly produced in it, or received by it
from different tissues, then tne excitation made on these nervous
centres becomes so powerful that convulsions are produced. This
is found in men and animals, even in perfect health. If the as-
phyxia is incomplete, convulsions are not produced, unless the
excitability of the spinal cord is greater than usual, and this is
the case in epileptics.

In November, 1851, at the Ecole Pratique, of Paris, I pub-
lished for the first time, before a class of about forty young
Physicians and Medical students, the results of my experiments
as regards the cauterization of the larynx in epilepsy. About
eight months after, Dr. Eben Watson published a paper* in

* Kemarks on Dr. M. Hall's theory of the relation of Laryngysmus to
Epilepsy. In London Journal of Medicine, July, 1852, pp. 641-43.

which he says : " The treatment I would now propose instead of
tracheotomy is simply the application of a solution of nitrate of
silver, varying in strength with the. requirements of the case, to
the glottis of the patient, with the view of diminishing the
nervous excitability of the part in question. A similar treat-
ment has been found by me remarkably successful in alleviating
and removing, in a short time, the susceptibility of the patient
to laryngysmus, in cases of hooping cough, and of spasmodic
'croup (laryngysmus stridulusj) nor can I see any reason why a
similar result should not ensue in chronic cases of epilepsy."

The reasons given by Dr. E. Watson are partly the same by
which I had been led long before him to perform the operation
he suggests. But I had also some other reasons. It is perfectly
known, in the actual state of Medical Science, that the great-
est changes may be produced in the nervous centres, as well as
in the nerves, by a very strong excitation of the termination of
the nervous fibres in the skin or the mucous membranes. On
this principle are founded many modes of treatment of some dis-
eases of the spinal cord and of neuralgia. The application of
caustics, blisters, cupping, hot iron, etc., is based on this princi-
ple. In accordance with it I am inclined to believe that epilepsy
might be cured by a mere application of a hot iron to the skin
of the neck ; at least I have had two guinea-pigs cured after such
an application, repeated three or four times.

The operation of tracheotomy proposed by Marshall Hall has
proved successful in some cases. But it is a dangerous operation,
and if it is proved that another one much slighter can produce
the same good effects, it ought not to be practised.

That other operation is the cauterization of the larynx ; it
prevents the closure of the glottis, and thus is able to cure
or to relieve epileptic patients as well as it cures some other
diseases. Every learned physician knows that it is sufficient to
cauterize the larynx once or twice to cure hooping cough in
almost every case.

When the cause of the epileptic fits is excessive, and when the
spinal cord is very excitable, to allow free breathing merely
will not be sufficient to prevent the general convulsions. But
their violence, if respiration is free, will be deprived of all the
effect that would be produced by the excitation of black blood
if breathing did not take place.

The distinction made between organic and inorganic epilepsy has
not the importance that some writers seem to admit. There
are alterations in the nervous system in both cases, and the only
difference is that these alterations can be easily seen with the
naked eye in one case and not in the other. I ought to point
out that the cases of epilepsy in animals, which I have cured,
were cases of organic epilepsy. These animals have been cured,
although the apparent and primitive cause of the disease, i. e. a
section of a lateral half of the spinal cord, continued to exist.

The cauterisation of the larynx on these animals was made
every day, or every other day, and sometimes during two or three
months. In some cases, the relief having been immediate, the
cauterisation was made only twice a week. One of the
animals experimented on was cured after three or four cau-
terisations ; but the number of cauterisations necessary has been
generally very much greater. When I left France in February,
1852, I had cured about a third of the animals treated by this
method ; and all the others, except two or three, had been very
much relieved, and certainly many of them would have been cured
if the treatment had been prolonged.

I knew that an animal was cured, not only by the absence of
spontaneous fits, but when I could not produce a fit by giving
great pain. I had found that on any epileptic animal, except im-
mediately after a paroxysm, I could very easily produce a fit by ex-
citing pain and more particularly by pinching or burning the skin
of the face or neck. So that I am authorised to believe that when
a fit was not produced by pinching or burning the face, it was
because epilepsy had ceased to exist.

Some physicians in this country have already tried on man
the mode of treatment that I have found so successful on animals.
From what I know of the results of their attempt, it seems to
me that man is like animals in this respect. There has not been
yet a complete curation : but, except in one case, there has been
a very considerable diminution in the frequency and the intensity
of the fits.

As physicians who have to treat epileptics, have not to
make experiments, but to cure by making use of all the best
means together, I think that the treatment of epilepsy ought

not to consist merely of the cauterisation of the larynx. The
plan of treatment I should suggest is the following :

1st. A cauterisation of the larynx with a strong solution of
nitrate of silver, (at least 60 grains to the ounce,) every day, for
at least five or six weeks,

2d. A cauterisation of the skin of the neck over the spine,
with a hot iron, once a fortnight, for about two or three months.

3d. Exercise and gymnastics.

4th. Make use of oxide of zinc or ammoniated copper, remedies
which a very respectable physician of Geneva, ('Switzerland,)
Dr. Herpin, has found successful in many cases, when their dose
has been considerable.*

5th. If in a fit of epilepsy the suffocation is very considerable,
the operation of tracheotomy ought then to be performed imme-
diately.

XXVI, — CUKE OF EPILEPSY BY SECTION OF A NERVE.

It is a well known fact that epilepsy may be produced by injury
to a nerve. Dr. John Cooke, in his Treatise on Nervous Diseases,
says on this subject : " From the writings of Forestus, Van Swie-
ten and Tissot, it appears that injury done to the nerves, or that
a morbid state of them, has in many instances given occasion to
epilepsy. In the Edinburgh Medical Essays and Olserv., a
case is related of a violent epilepsy, which frequently occurred,
which was produced by a hard cartilaginous substance, of the
size of a large pea, situated upon a nerve. That this was the
cause was evident, as the disease ceased on the extirpation of the
tumor. In the same we have an account of epilepsy depending
upon a calculus of an irregular figure, about the size of a nut,
pressing on a branch of the sciatic nerve ; and another in which
the par vagum was compressed by a concretion of a similar
kind." Darwin, in his Zoonomia, says, "I once saw a child
about ten years old, who frequently fell down in convulsions, as
she was running about in play. On examining, a wart was
found on one ankle, which was ragged and inflamed, which was
cut off, and the fits never recurred."

* See his admirable work: Du Pronostic et du Trailement de V Epilepsie.
Paris, 1852. Ouvrage couronne par PInstitut de France.

Van Swieten relates a case of curation of epilepsy by the ex-
tirpation of a hard cartilaginous body, somewhat larger than a
pea, situated on a nerve of the leg.

A case is related in the Medical and Physical Journal, (vol.
x. p. 52,) in which a cure of epilepsy was effected by the
application of caustic to the nerve which accompanies the vena
saphena.

Many other analogous cases are on record. Jacques Carron,
(Recueil periodique de la Soc. de Medecine de Paris, t. xviii. p.
422,) cured a child by the extirpation of a small sebaceous
tumor which existed on one of the fingers. Portal, (Observations
sur Tepilepsie, Paris, 1827, p. 159,) cites a case observed by
Fabos, in which the fits were preceded by a pain in one of the
fingers. During a violent fit Fabos put a ligature around the
radial nerve, and the patient was completely cured. Portal
(Anatomic Medicale, vol. iv. p. 247,) relates that one of his
pupils, Mr. Leduc, cured an epileptic by the extirpation of
a hard tumor which was on one of the fingers. Joseph Frank
cured by castration a patient in whom epilepsy had appeared
after an injury to the scrotum. Henricus ab Heer, cited by
Sennert, (Opera omnia, vol. ii. p. 489,) having observed that
during her fits, a girl used to rub her two big toes, cured her
by the application of caustic to these toes. Similar cases have
been related by Alexander, of Tralles, and by Wepfer.

I have cured a guinea-pig of a very violent convulsive affec-
tion, much resembling epilepsy, by a section of the sciatic nerve.
This animal had been bitten by another on the toes of one of the
posterior limbs. A considerable slough appeared on the wounded
part, and after two or three weeks fits appeared, and the animal
shortly afterwards had many very violent fits every day. I laid
bare the sciatic nerve and cut it transversely. After this opera-
tion I kept the animal many months, and never saw it have a
fit. From this fact, and from those observed by many physi-
cians above related, it appears clearly that in cases of
epilepsy it is necessary to examine if there is no injury whatever
to some nerve, and more particularly when the aura epileptica
exists. If there is such an injury, the treatment ought to be
either the section of the injured nerve or the removal of the
tumor, if there is one, and sometimes the application of a caustic
or a blister.

XXVII. — LAWS OF THE DYNAMICAL ACTIONS IN MAN AND ANIMALS.*

The following laws are based upon a very considerable number
of facts which I have observed or found on record in many books,
pamphlets and journals. I have collected these facts and I in-
tend to publish them in a special paper.

I ought to say that many Physiologists, and more particularly
Fontana, Delaroche, Adamucci, Broussais, Buchez, Re'veille'-
Parise, J. Mueller, J. Paget and Carpenter, have pointed out the
existence of some parts of some of these laws.

1. Nervous actions, muscular contraction, contraction of the
cellular tissue, the, discharge of the electrical apparatus of some
fishes, the galvanic current of certain organs, the galvanic dis-
charge which accompanies the muscular contraction, and probably
also the phosphorescence of certain animals and the ciliary move-
ments, are phenomena which cannot exist without being attended
with an organic waste which nutrition alone can provide for.

2. The faculty of originating these phenomena has a tendency
to increase in direct ratio to the rapidity of the circulation of
blood, to its abundance, and to the amount of its nutritive ma-
terials, both general and special.

3. During rest, i. e. at the time of the non-existence of these
phenomena, the tendency of such a faculty towards augmenta-
tion meeting with no obstacle, augmentation actually takes
place.

4. The increase is much more rapidly effected when an action
has just been performed, than it is after a prolonged rest.

5. Nutrition becoming altered in the tissues which remain in-
active for a long time, the faculty of producing the above-men-
tioned phenomena diminishes by degrees, and even finally
disappears when the structure of the tissues has been deeply
modified.

6. The faculty of originating these phenomena increases in
direct ratio with the length of the rest, within certain limits ;
and when the latter are overleaped, there is a period when no
change takes place ; but afterwards the faculty decreases, on
the contrary, in direct ratio with the length of the rest.

* I ought to say that these laws and the facts upon -which they are esta-
blished, have been the subject of many communications that I have made to
the Societc de Biologic, at Paris, in the year 1848.

7. For many tissues which produce these phenomena a com-
plete rest is scarcely possible. The phenomena take place, in
appearance, spontaneously, and with as much energy as the
temperature is higher.

8. The faculty of producing these phenomena decreases at the
time they are going on, in proportion to their intensity and
duration, and in inverse ratio to the nutritive reparation which
simultaneously takes place.

9. Reparation thus incessantly supplying for expenditure, it
is not possible, with regard to most of these phenomena, and as
long as circulation goes on, to destroy entirely the faculty of
originating them ; or rather, as soon as we have succeeded in
destroying that faculty, it is reproduced by nutrition.

10. Expenditure dependent upon action, being followed by a
great activity in the nutrition, it happens that, if the action be
frequently renewed, there is an excess of nutrition and a consi-
derable increase of the faculty of acting.

11. When the faculty of acting has been increased in virtue
of the preceding reasons, within a certain limit, an equilibrium
exists between the expenditure and the reparation, and the in-
crease no longer takes place.

12. As it is possible for nutrition to take place in the tissues,
although the nutritive fluid is not actually circulating in them,
and provided that a certain amount of it exists in them, the
faculty of acting may be increased in parts where circulation is
stopped.

13. Although circulation and consequently reparation, are
more active in summer than in winter time, at least in cold-
blooded animals, the faculty of acting becomes more consider-
able in winter than in summer time, because the spontaneous
expenditures abovementioned, and those due to external stimuli,
or dependent upon the will, are by far less considerable.

All the preceding laws may be summed up in the following :
The intensity of the faculty which animal tissues possess, of
producing the vital phenomena, seems to be in a direct ratio to
the intensity and duration of the nutritive reparation, and in an
inverse ratio to the intensity and duration of the existence of
these phenomena.

XXVIII. — INFLUENCE OF RED BLOOD ON MUSCLES AND NERVES
DEPRIVED OF THEIR VITAL PROPERTIES.

James Phillips Kay* has found that blood, injected into limbs
of dead animals, just after irritability has disappeared, is capable
of regenerating this vital property. I have gone much farther, and
have discovered that blood is able to regenerate the vital proper-
ties of nerves and muscles, even in limbs which have lost their
irritability and have been rigid for several hours. I have ob-
tained this result from the following experiments :

1st. On the body of a rabbit, in which cadaveric rigidity had
already existed for 10, 20, and in one case, 33 minutes, I
divided the aorta and the vena cava in the abdomen, immediately
above the bifurcation of these vessels. By means of small tubes,
a communication was established between their peripheric ex-
tremity and the central extremity of the corresponding vessels
divided in a living rabbit. The blood of this living animal
circulated immediately in the posterior limbs of the dead one.
After about six, eight or ten minutes, rigidity disappeared,
and, a few minutes afterwards, movements took place when
I excited the muscles or the muscular nerves.

2d. I have obtained a like result from an experiment more
easily made than the preceding, and which I have performed
more frequently. I divided transversely the body of a living
guinea-pig, or rabbit, into two halves, on a level with the lower
border of the kidneys, leaving no communication between the
two halves, except by the aorta and the vena cava. I then tied
the aorta immediately below the origin of the renal arteries.
The muscular irritability gradually diminished, and in a very
variable length of timef it gave way to cadaveric rigidity. I
waited until rigidity had been fully developed in all the muscles,
and then the ligature was relaxed and the circulation re-es-
tablished. Rigidity disappeared slowly, and the muscles and
the motor nerves resumed their vital properties.

3d. In order to ascertain if voluntary movements and sensi-
bility could be restored to limbs that had been in a state of ca-

* Treatise on Asphyxia. London, 1834

t Sometimes 30, 20, or even only 10 minutes in weak animals, and from
1 to 8 or 9 hours in strong animals.

daveric rigidity, I tied the aorta immediately behind the origin
of the renal arteries, in several rabbits. Shortly afterwards,
sensibility and the voluntary movements disappeared in the
posterior limbs. I waited until muscular irritability had given
way to what is called cadaveric rigidity ; and when that peculiar
rigidity had existed for at least twenty minutes, I relaxed the
ligature. Then circulation took place, and, in consequence of it,
sensibility and voluntary movements re-appeared.

From this experiment it results, that not only local life, but all
the properties and actions of full life, can be restored in limbs
that have been in the state called rigor mortis, cadaveric or
post-mortem rigidity.

4th. On a man, 20 years old, who was guillotined on the
18th of June, 1851, in Paris, I made an experiment similar
to some of the preceding. The decapitation took place at
8 o'clock A. M. Ten hours afterwards, i. e. ten minutes after
6 o'clock P. M., the muscles of the hand, upon which I intended
to experiment, exhibited some slight manifestations of irritability.
At 7 and at 7* o'clock P. M. I ascertained that they had lost
their irritability. Shortly after they were in a state of cadaveric
rigidity.

I began the injection of blood 10 minutes after 9 o'clock P. M.

As I wished to inject fresh human blood, and as I could not
obtain any from the hospitals at such an hour, I was obliged to
make use of my own. My friends, Drs. F. Bonnefin and Des-
lauriers, drew from one of the veins of my left arm half a pound
of blood, which was immediately beaten and completely defibri-
nated and filtered through a cloth.

As, in opposition to the general opinion, I had found that it is
not necessary, in transfusion, to make use of blood at a tempera-
ture not far from that of warm-blood animals, I left the blood
employed in this experiment freely exposed to the atmosphere
during all the time of the operation. The temperature of the
air was 19° centigr. (66°-2 Fahr.j I regret not having taker*
the temperature of the blood when I began to inject it, but rt
was probably about the same as that of the atmosphere.

The injection was made into the radial artery, a little above-
the wrist. The whole quantity of the blood was injected in about
8 or 10 minutes. The arm operated on had been separated from

the body, and the blood injected came out from all the divided
arteries and veins.

Having saved nearly all the blood which flowed from these
vessels, I injected it anew. The last injection was made 45
minutes after 9 o'clock P. M. Ten minutes afterwards I found
that cadaveric rigidity had ceased in the hand, and that two
muscles only, out of the nineteen existing in that part, had not
resumed their irritability. Three muscles had become so very
irritable that a slight mechanical excitation was followed by a
contraction in the whole length of their fibres.

At half past one o'clock A. M., — seventeen hours and a half
after decapitation and four hours after the injection of blood, —
there was still a slight irritability in the muscles of the hand.

In this experiment I found that half a pound of defibri-
nated human blood was sufficient to give irritability, for seve-
ral hours, to seventeen of the muscles of a hand.*

5th. An experiment on another guillotined man gave me
more interesting results. The decapitation had taken place
at 8 o'clock A. M. on the 12th of July, 1851. At 5£ o'clock
P. M., cadaveric rigidity existed in almost all the muscles of
the arms and fore-arms. I separated them from the body, and
at G| o'clock I ascertained that cadaveric rigidity was increased,
and that only a few muscles were still slightly irritable. At 8
o'clock P. M, (12 hours after the decapitation) the muscles of the
two arms were completely deprived of irritability, and in full rigi-
dity, and the muscles of the forearms contracted only locally under
the influence of a mechanical irritation, and not at all when ex-
cited by a powerful magneto-electric current. Two other exami-
nations made, one at 9j and the other at 10 o'clock, gave the
same results.

At 10 J o'clock two or three bundles of fibres of one of the
muscles of the fore-arm were the only parts where a mechanical
excitation produced a slight local contraction. All the other
muscles were perfectly stiff and deprived of irritability.

Twenty-five minutes after 10 o'clock there was no appearance
of irritability remaining in any muscle.

I then began the preparations for the injection of blood, with

* For a full account of the circumstances of this experiment, see my paper
>in the Gaz. Medic.de Paris, i. vi.— 1851, p. 421.

the assistance of Drs. Martin-Magron, F. Bonnefin, Crouzet, and
Mr. Moyse.

We drew about a pound of blood from the carotid of a strong
dog. The blood was beaten and defibrinated before coagulation
could take place in it, and 10 minutes after 11 o'clock the injec-
tion was begun. It was made in the brachial artery of the left
arm, in the middle of its length, where the arm had been ampu-
tated. As soon as the blood had been thrown in the artery,
some reddish spots appeared in different parts of the skin of the
fore-arm, of the hand, and more particularly of the wrist. These
spots became larger and larger, and the skin had the appearance
it has in rubeola. Soon after, the whole surface of the skin was
of a violet reddish hue. In a few minutes this color disappeared,
and was replaced by the natural hue of the skin during life. The
skin became elastic and soft, as in a living man, and we saw the
bulbs of its hair becoming erected and presenting the appearance
called eutis anserina. By increasing and diminishing alternately
the impulsion given to the blood, we succeeded in producing the
beatings of the pulse in the radial artery. The veins were dis-
tinct and full as during life.

A short time after, the fingers, which had been extremely stiff,
relaxed, and rigidity disappeared also in the other parts of the
limb.

Forty-five minutes after 11 o'clock P. M., irritability had re-
turned in all the muscles of the limb operated on. The degree
of irritability, more particularly in the muscles of the arm, (tri-
ceps, biceps and others) was very considerable, and much greater
than I had seen it at the time the corpse was first examined
(about five o'clock P. M.) Irritability was still present in almost
all the muscles of this limb at 4 o'clock A. M., (20 hours after
the decapitation,) when I was obliged, from extreme fatigue, to
abandon further investigation.

The blood injected was at 23° centig. (73°.4 Fahr.) when I
began the operation, and the atmosphere was at 19j° centig.
(66.66 Fahr.)

In this experiment, about one pound of defibrinated dog's
blood gave irritability for more than five hours to all the
muscles of a limb, from the middle of the arm to the hand.

6th. Every one knows the singular fact, that Vibriones and

other Infusoria, when desiccated, will live when they are put into
water. It is also perfectly known that seeds, after many centu-
ries, may grow when put in the earth. I have found something
of the same kind in higher organisms ; it is that muscles, in a
certain condition, after having been separated from the body
for many days, may recover their irritability.

Dr. Coze, of Strasbourg, has found that chloroform injected
into the main artery of a limb produces instantly the strongest
rigidity, and that if blood is allowed to circulate again in the
limb, life appears again in it. I have gone farther, and found
that if a limb, in which an injection of chloroform has been made,
is separated from the body, it is able, under the influence of an
injection of blood, to recover its muscular irritability 2, 3, 4, 5
and (in one case) 10 days after the rigidity was produced.
1 think Mr. Edouard Robin is right in admitting that chloroform
prevents the chemical changes that take place in organic bodies
after death, and, if it is so, we can understand why an injection
of blood made so long after the limb has been separated from the
body, may reproduce irritability. One day is not more than one
hour, if, during it, there is no alteration produced in the muscles.

It appears, nevertheless, that chloroform does not entirely
prevent the alterations of muscles, because, in my experiments, I
have found that the longer the limbs had been separated from
the body, the greater was the quantity of blood necessary to re-
produce irritability.

7th. I lately made an experiment, with the view of ascertain-
ing how long a limb, separated from the body of an animal, may
be kept alive by means of injected blood. I succeeded in
retaining local life in one of the limbs of a rabbit more than
41 hours. The animal was a very vigorous, full grown one. I
killed it by hemorrhage, and, two hours afterwards, rigidity had
begun in most of the muscles of the two posterior limbs, and only
a few bundles of muscular fibres had still a slight irritability. A
first injection of defibrinated blood was then pushed in the femo-
ral artery of the right posterior limb. Fifteen minutes after the
beginning of the injection, local life fi. e. irritability) was re-
stored in the limb receiving blood, and cadaveric rigidity had
disappeared.

The manner of testing this irritability was the same as that of

Glisson, Gorter, and all the experimenters of the two last centu-
ries,— I mean by mechanical excitation. I did not use galvanism,
as it exhausts muscular irritability too much, as Autenrieth,
Pfaff and many other observers have shown long ago. Being
aware of this fact, I have always, in my preceding experiments,
made use of galvanism for a very short time only.

Three hours after the death of the rabbit, irritability still
existed in the right limb (the injected one,) while the left was
perfectly rigid and had not the slightest irritability. Half an
hour later, rigidity had begun again in the right limb ; blood
was injected anew, rigidity disappeared, and local life returned.
From this moment until 11 o'clock, P. M., (death liad occurred
at 6 o'clock, A. M. of the same day,) blood was injected many
times. Rigidity did not return, and the vital property of the
muscles was maintained. Of course the left limb, during that
time, remained rigid, and had not the slightest irritability.

From 11 o'clock, P. M. until 6 o'clock, A. M. the succeeding
day, an abundant injection of blood was made every twenty or
twenty-five minutes. The irritability was not powerful, but it
existed in all the muscles of the limb. There was no rigidity
at all.

The injections were then made more frequently — once in each
quarter of an hour — until three o'clock, P. M., at which time I
was obliged to stop them for an hour and a half.

At half past four I found the limb rigid, and only a few
bundles of muscular fibres still irritable. A very abundant
injection was then practised, and rigidity soon disappeared,
giving way to irritability. From this time to 11 P. M., a great
many injections were made, and irritability was maintained. I
was then obliged to give up the experiment. At that moment
irritability was strong in all the muscles of the injected limb,
except some parts of their pelvic extremities that had not
received a sufficient quantity of blood.

The next morning that limb was in full and energetic rigidity.
The other limb had already lost its rigidity, and had an evident
smell of putrefaction. The third day after the death of the
animal, rigidity was strong in the injected limb, while the other
was in an advanced state of putrefaction.

If we compare these two limbs, we find, 1, That the injected

one had a strong irritability at the end of forty-one hours after
the death of the animal ; 2, That its rigidity gave way to putre-
faction only at the eightieth hour ; 3, That it was in complete
putrefaction only at the ninety-fourth hour. The other limb
was in full rigidity at the fifth hour after the death of the
animal ; its rigidity gave way to putrefaction at the forty-
eighth hour ; and it was in complete putrefaction at the seven-
tieth hour.

From all the experiments above related, it appears that life
may be reproduced or maintained in muscles and nerves by
mere injections of blood. I have found, also, that life may be
reproduced by the same means in the spinal cord and in the
brain. I will publish these facts in another article.

It is nearly indifferent in these experiments whether we use
venous or arterial blood ; but it is absolutely necessary to employ
red blood, i. e. oxygenated blood.

I have tried, sometimes, arterial blood, rendered black by
the substitution of nitrogen or hydrogen for a great part of its
oxygen, and I have found that such blood was unable to repro-
duce the vital properties of nerves and muscles.

Oxygen is necessary, either because it prevents the blood-glo-
bules from being altered, or because it acts directly on muscles, as
Gustavus Liebig has found it does on their external surface,
when exposed to air. I believe it is necessary for both these rea-
sons.

I cannot say how long after the beginning of cadaveric
rigidity in a muscle, oxygenated blood can reproduce local life.
In the second of the two decapitated men, on whom I ex-
perimented, rigidity had existed at least five hours before the
injection was begun. I believe that the stronger the animal is,
the more easy it is to reproduce local life in rigid limbs, by
injection of blood. In limbs of weak rabbits, I have found it
impossible, two hours after the beginning of cadaveric rigidity,
to reproduce local life. In a very strong dog I have reproduced
muscular irritability four hours after rigidity had been fully
developed.

Ten, twelve, or fourteen hours after rigidity had taken place,
in human limbs, I have tried in vain to re-establish local life.

I have ascertained that pure serum of blood, or milk, or albu-

men of eggs, are unable to produce any apparent change in
rigid limbs.

The following conclusions are to be drawn from the facts
related in this article :

1st. Red blood, i. e. richly oxygenated blood (arterial or
venous) is able to revive irritability in muscles, four or five hours
after these organs have lost this property.

2d. Red blood is able to revive the vital properties of
nerves and nervous centres, when these properties have not been
lost for more than about an hour.

3d. Muscular irritability can be maintained for more than 41
hours, by mere injections of blood, in limbs separated from the
body of a rabbit.

4th. Muscular irritability may be re-established in limbs ren-
dered rigid by chloroform for many days, even ten days.

XXIX CASES OF LOSS OF SENSIBILITY ON ONE SIDE OF THE BODY.

AND LOSS OF VOLUNTARY MOVEMENTS ON THE OTHER SIDE.

It has been objected to me that if the transmission of sensitive
impressions, in the spinal cord, takes place, as I have tried to
prove in a former part of this sketch (Art. XIX,) so that those
coming from the left side of the body, are mostly conveyed to
the sensorium along the right side of the spinal cord, — et vice
versa — physicians should have some times found in man the
same thing that I have discovered in animals.

Many reasons have prevented physicians from making such a
discovery: In the first place, an injury or a pathological altera-
tion, limited to a lateral half of the spinal cord, is very rare.
Besides, the idea that there is no crossing of fibres in the spinal
cord, has been an obstacle to a thorough examination of many
pathological cases, and it has been so in a case observed by Boyer.

There are but few cases on record in which there was a loss
or a diminution of sensibility on one side, and of voluntary
movements on the other. I will give here a short account of
some cases of that kind, which are very interesting.

The first one I will relate has been observed by Boyer:

A drummer, of the National Guard of Paris, received a wound
in the back of his neck. A sword had been thrown at him, and
had penetrated the superior part of the right lateral half of the

neck. An incomplete paralysis of movement took place in the
right side of the body, and, some time after, it was accidentally
discovered that sensibility was lost in many parts of the left
side of the body. After twenty days the wound was cured, and
the man went out of the hospital, still paralysed.

From what we know of that case, it appears that the sword had
incompletely divided the right lateral half of the spinal cord.
The paralysis of motion on the right side of the body was
certainly produced by the division of a part of the anterior
column, and, as the instrument had penetrated the right side of
the back of the neck, it must have divided the parts between the
anterior column of the spinal marrow and the external surface of
the right side of the neck. These parts, besides the muscles and
bones, are the lateral and posterior columns and the gray matter
of the right half of the spinal cord. So that in this case nearly
the same injury and also the same morbid phenomena had ex-
isted as in the animals on which I have divided a lateral half of
the spinal cord.

The following case is still more interesting. It has been re-
corded by Dr. R. Dundas, Surgeon of the Hospital of Bahia.

A mason fell on his back from an height of 20 feet. After
having recovered his consciousness, he discovered that all the
left side of his body, from the shoulder to the foot, was paralyzed
as to motion, without the slightest alteration of sensibility, and
that the right side in which the movements were free, was com-
pletely deprived of sensibility.

Three important facts, precisely like those I have discovered
in animals after the transversal section of a lateral half of the
spinal cord, existed in this case :

1st. A morbid exaltation of sensibility in the side where move-
ment was lost.

2d. A diminution of temperature in the side where the para-
lysis of sensibility existed.

3d. An increase in temperature in the side where the paralysis
of movement existed.*

* In a former part of this sketch (Art. xxii.) I have related facts proving
that animal heat may be increased after injuries to the spinal cord. I have
learned since, that Prof. D. Gilbert has observed a case of fracture of the
spine, in which the temperature of the paralyzed parts was increased. Prof.
Dunglison has also stated that the paralyzed side in hemiplegic patients
may have an elevation of temperature.

When Dr. Dimdas published this curious case, the patient was
living and improving ; so we do not know what was the altera-
tion existing in the spinal cord.

H. Ley, in a letter to Sir Charles Bell, relates the following
case :f

Mrs. W., after a profuse hemorrhage, became paralytic. Upon
one side of the body there was a loss of sensibility, without, how-
ever, any corresponding diminution of power in the muscles of
volition. The breast, too, upon that side, partook of the insen-
sibility, although -the secretion of milk was as copious as in the
other. She could see the child sucking and swallowing, but she
had no consciousness, from feeling, that the child was so occu-
pied.

Upon the opposite side of the body there was defective power
of motion, without, however, any diminution of sensibility. The
arm was incapable of supporting the child ; the hand was power-
less in its grasp ; and the leg was moved with difficulty, and with
the ordinary rotatory movement of a paralytic patient ; but the
power of sensation was so far from being impaired that she con-
stantly complained of an uncomfortable sense of heat, a painful
tingling, and more than the usual degree of uneasiness from
pressure, or other modes of slight mechanical violence.

She again proved pregnant. Her delivery was easy : but after
about ten days she complained of numbness on both sides.
Her articulation was indistinct ; she became more and more in-
sensible, and sank, completely comatose.

No positive disorganization of the brain could be detected.
The ventricles, however, contained more than usual serum ; and
there were found thickening and increased vascularity of the
membranes, with moderately firm adhesion in some parts ; in
others, an apparently gelatinous, transparent and colorless de-
posit interposed between them.

Unfortunately, no examination of the spinal cord was made.

In this case there was very likely, as in my experiments, an
increase in the temperature of the side paralyzed of motion. The
writer merely says that the patient was constantly complaining
of an uncomfortable sense of heat. There was, as in my animals,
an evident increase in sensibility on that side.

fThe nervous system of the human body. By Ch. Bell. 3d ed. London,
1844, p. 245.

M. Monod* has related the case of a man who, after having
felt a sudden pain in his back, became paralyzed in the motion
of the right inferior limb. Sensibility was entire on this side,
but on the left side, where the movements were entire, sensibility
was entirely lost from the breast to the foot. There was at first
no fever. The patient died 34 days after the beginning of this
affection.

The brain and its membranes were normal. A hemorrhage
had taken place, and blood was found in the right side of the
central gray matter, in the neighborhood of the anterior column
in the dorsal and lumbar regions.

This case is assuredly a very remarkable one, and in accord-
ance with my experiments.

The conclusion to be drawn from these four cases is, that in
man as well as in animals, there appears to be a crossing of the
sensitive nerve-fibres in the spinal cord.

XXX. — ON THE DIFFERENT DEGREES OF EXCITABILITY OF THE
DIFFERENT PARTS OF THE SENSITIVE NERVE-FIBRES.

It is a well-known fact, that an excitation of the skin or of a
mucous membrane, produces a greater pain or a greater reflex
action than that of the nerve trunk, from which these parts re-
ceive their nerve-fibres. For instance, a slight excitation of the
laryngeal mucous membrane produces coughing, while an excita-
tion of the vagus nerve very rarely produces the same effect.
Therefore, there is a notable difference between the peripheric
extremity of a nerve-tube and its part contained in a nerve-
trunk.

The existence of a peculiar organ in the skin (the corpuscles
of touch of Wagner) has not much (if it has anything) to do with
the different degrees of excitability of nerve-tubes in the skin
and in the trunks of nerves. The corpuscles of touch do not
exist in the mucous membranes, and if they exist in the skin of
frogs, turtles, etc., it is in a very small number ; and, neverthe-
less, the degree of excitability of nerve-fibres in these parts is
much superior to that of the fibres of the nerve-trunks.

Some very striking differences exist in the degree of excita-

* Bulletin de la Societe Anatornique, No. xviii. p. 349.

bility of centripetal nerve-fibres in the five following different
parts of their length.

1st. The part contained in the skin.

2d. The part of a nerve extending from the skin to the spinal
cord.

3d. The posterior roots of the spinal nerves.

4th. The part of the posterior roots attached to the spinal
cord.

5th. The part of the cutaneous nerve-fibres contained in the
gray matter of the spinal cord.

The fibres existing in the gray matter of the spinal cord ap-
pear to be inexcitable, at least by our ordinary means of excita-
tion. Of the four other parts, the less excitable is the nerve be-
tween the ganglion and the skin. The excitability of the pos-
terior roots is less than that of the skin and that of their part
attached to the spinal cord. Of these two last parts the skin is
less excitable than the other.

I measured the excitability by the degree of pain or of reflex
action. The differences are much more easily found for the re-
flex action than for the pain.

Is it because they have been connected with the cells of the
central gray matter of the spinal cord, that the centripetal fibres,
contained in that gray matter, are not excitable ? If it is so,
there is a difference between these cells and those of the gan-
glions on the posterior roots, because the connection of these fibres
with the cells of these ganglions does not prevent their being
excitable.*

From the facts above related I conclude that the same nerve-
fibre, in different parts of its length, may have very different de-
grees of excitability.

XXXI. — THE AUDITIVE NERVE IS A NERVOUS CENTRE.

In an anatomical point of view there is no doubt that the
auditive nerve is a nervous centre. This is proved by the fact
that cells of gray matter are found, not only in the terminal part
of the nerve, but also in its trunk, in many animals, according
to the researches of Stannius, Corti, Kb'lliker, and myself.

In a physiological point of view, the fact I have discovered,
(see Art. V. p. 21,) viz., that any injury to the acoustic nerve

100

produces turning, is sufficient to prove that it is a nervous centre.

The degree of pain produced by an excitation of this nervous
centre appears to be as considerable as that caused by a similar
excitation of the trigeminal nerve. I will publish soon an ac-
count of the strange effects produced in different parts of the body
in consequence of an injury of that nervous centre. I will merely
say here that, after such an injury, there are muscles which
appear to be slightly paralyzed. Besides, there seems to be a
notable hyperaesthesia of the skin everywhere.

Flourens has found that a section of the semi-circular canals
in birds and some mammals produces a peculiar disorder in the
movements of the head, and, in some .cases, turning. He says
that the auditive nerve must be considered as composed of two
nerves: one going to the semi- circular canals and possessing a
peculiar power on the movements of the body, and the other,
the vestibular or true auditory nerve. What I have found on
frogs is in opposition to these views. A section of the semi-
circular canals, in these amphibia, does not produce any effect
on the movements of the body, and the slightest excitation of
the true auditive nerve is sufficient to produce pain, hyperaesthe-
sia, turning, and other strange effects on many muscles of the
body.

I have sometimes seen turning produced after the mere laying
bare of the kind of bladder, containing the terminal part of the
auditive nerve, in frogs. So slight may be the excitations on
that nerve sufficient to produce turning, that very likely turning
after the laying bare of that bladder was the result of some
slight mechanical injury of the nerve. The rapidity of turning
and the smallness of the circle then described are in proportion
to the degree of injury to the nerve. When the two auditive
nerves are injured, the animal turns on the side most injured.
Sometimes, instead of turning, the animals roll around the longi-
tudinal axis of their body; this takes place in very strong
animals after the terminal part of the nerve has been entirely
crushed.

In frogs deprived of their cerebral lobes, the same effects are
produced after injuries of the auditive nerve, as in unmutilated
frogs.

101

XXXII. — ON APPARENTLY SPONTANEOUS ACTIONS OF THE CONTRAC-
TILE TISSUES OF THE ANIMAL BODY.

All the contractile tissues of the animal body (the muscles of
the trunk and limbs, the muscular layers of the digestive canal,
the iris, the uterus, the dartos, the cellular tissue, etc.) present,
sometimes, apparently spontaneous contractions. I give this
name to contractions which are not the result of an external
excitation or of an excitation produced by the nervous system on
the contractile tissues. These contractions may be permanent
or momentary, rhythmical or irregular, slight or very powerful.
One of their causes, if not their only cause, appears to be an
excitation directly produced on the contractile fibres by the
carbonic acid existing in the blood.

1. Contractions in the muscles of the face after a section of the
facial nerve. — My friend Dr. Martin-Magron and myself have
discovered that after the section of one of the facial nerves, on a
rabbit, the face becomes very quickly deviated, not on the healthy
side, as it is known to be in man, but, strange to say, on the
paralysed side. The deviation, very slight at first, increases
gradually during one or two weeks, and then it is so considerable
that the middle of the lips is at a distance of four, five or six
lines from its natural situation. There is an evident state of
contraction in all the paralysed muscles. When the animal is
excited, or when its respiration is somewhat disturbed or pre-
vented, the paralytic muscles tremble, and sometimes they have
rhythmical contractions and relaxations.

The contractions of these muscles may be so considerable that
the bones themselves, and, secondarily, the teeth, may be de-
formed. In one case, on a rabbit which I had kept living twenty-
one months after the extirpation of one of the facial nerves, not
only the superior and inferior jaws were by far less developed on
the paralysed side than on the other, but the anterior part of
the superior maxillary bone was deviated towards the paralysed
side, so that the middle line of the roof of the mouth was curved
and presented a great concavity on the paralysed side and a cor-
responding convexity on the other.

When the two facial nerves have been divided, there is no

102

deviation, but there is an evident state of contraction in all the
paralysed muscles, particularly around the lips.*

When one of the facial nerves is divided on a dog, on
a cat, or on a guinea pig, there is generally no deviation
on either side. But very frequently there are convulsive move-
ments, and sometimes rhythmical contractions, in the para-
lyzed side of the face. One of these two kinds of movements
always exists in young cats. They are increased, or produced
when they do not exist, in dogs and guinea-pigs, almost every
time we prevent the animal from breathing freely. Once, on a
very vigorous guinea pig, upon which one of the facial nerves
had been torn away, I saw alternate contractions and relaxa-
tions taking place, without a relapse, for eight or ten days after
the operation in the paralysed muscles. After that time, these
tremblings appeared only when the circulation and the respira-
tion were rendered very active, or when the respiration was pre-
vented or diminished. In the case of an impaired respiration,
the strength and frequency of these movements were in propor-
tion to the degree of asphyxia. During many months, the same
phenomena existed in this animal.

I ought to say that in all the experiments above related, the
nerve could not have any share in the movements, because,
the fifth day after the division, or after the extirpation of a
portion of it, the peripheric part had entirely lost its vital
property.

In man, as Dug£s justly remarks, as long as there is no
attempt at movement, voluntary or emotional, the face remains
without any deviation, in cases of facial hemiplegia, which have
not lasted a long time.

2. On spontaneous rhythmical or irregular contractions in
muscles of animal life, after death — It is a very important fact
in connection with the theory of the action of the heart, as I
will try to prove hereafter, that other muscles, and particularly
muscles of animal life, are capable of having rhythmical move-
ments. This fact I have discovered in the following cases :

a. After the division of the nerves of the ischiatic and lumbar

* Dr. Martin-Magron and myself have found that death occurs from inani-
tion in all the species of mammals on which we have divided the two facial
nerves. After the operation they cannot swallow : we do not know why.

103

plexuses, on one side, in mammals, if we suddenly asphyxiate
the animal, we see, at first, convulsive movements in the three
limbs and in other parts of the body not paralysed. After one,
two or three minutes, these movements cease, and there are only
some tremblings in the muscles of these parts. The paralysed
limb has no movement at all during one or two minutes, after
which time, suddenly, contractions in many bundles of muscular
fibres partially take place. In the same bundle the contractions
sometimes appear to come regularly one after the other. In
some cases I have seen, besides these tremblings, movements of
the entire limb, consisting of some successive flexions and exten-
sions of the limb, and after these movements had ceased, con-
tractions limited to various bundles of fibres appeared. In these
cases the action of the muscles began very late after death, and
once, only six minutes after the beginning of asphyxia, which
lasted two minutes and a half.

b. Nearly the same movements of which I have spoken as
existing frequently in the face, during life, in rabbits and guinea-
pigs, after the section of the facial nerves, exist always, either
during agony or a little after death. They are generally pro-
duced by partial contractions and relaxations of the different
bundles of fibres of the various muscles. It is rare to see all
the bundles composing one muscle contracting together. These
phenomena last five, six or eight minutes after the last respi-
ration. There are also such movements in the face during agony
and after death, when the nerves have not been cut and when
there is no paralysis ; but then the movements appear later and
do not last so long as in paralysed muscles.

c. I have seen in many rabbits apparently spontaneous rhyth-
mical contractions in the respiratory muscles. In about ten
rabbits, out of forty or fifty, the following phenomena were
very decided ; on the others they were slight, and sometimes
very slight, but in all cases a part of them always existed.
I open the abdominal cavity and expose the bowels to the action
of a cold atmosphere, so as to lower the temperature of the
animal ; after some minutes I make a little opening in one side
of the chest, and, at last, after a few minutes more, I open
largely one side of the chest. Generally, in such circumstances,
the respiratory movements continue to take place with energy.

104

I then take away the sternum and divide the two diaphragmatic
nerves. The movement of the diaphragm, nevertheless, continues,
and it exists rhythmically together with the movements of the
other respiratory muscles. Six, eight or ten minutes afterwards
the movements of the diaphragm are still regular, (there are from
five to twenty contractions in a minute ;) the intercostal muscles
present then only partial contractions. The different bundles of
fibres of these muscles contract separately one after the other,
but the same bundle has generally regular contractions and re-
laxations. At that time I destroy the spinal cord, and see that
the movements of the diaphragm and of the intercostal muscles
are not changed after this operation ; they last for nearly a quar-
ter of an hour, and in some cases much longer ; their regularity
subsists. In the diaphragm, long after the general movement
has stopped, there are regular or irregular contractions of
many bundles of fibres for one, two, three hours, and sometimes
more.

3. Deviation of limbs produced by a contraction of paralysed
muscles. — In pigeons, after the destruction of all the lumbar part
of the spinal cord, the two posterior limbs are completely para-
lysed. The muscles then are soft, and the different parts of the
limbs do not resist at all, when we try to put them in flexion or in
extension. But after a few days the paralysed muscles become
harder, and after a few weeks there is an evident state of con-
traction in them. The limb is generally kept in a state of exten-
sion, and deviated on one side or the other. The deviation
becomes considerable after some months.

Very likely it is owing to the same cause that club-foot and
other deviations are produced in embryos, after a destruction or
an absence of development of the spinal cord.

4. Rhythmical movements in the eye of the Ink-fish. (Loligo
sepia, L.) — The ciliary muscle so well described by Dr. W. Clay
Wallace, of New York, in the eyes of superior animals, is strongly
developed in the ink-fish. After an eye of this mollusc has been
separated from the body, I have sometimes found very singular
and perfectly rhythmical movements produced by the ciliary
muscle. These movements consisted in alternative contractions
and relaxations of some parts of that muscle. At every contrac-
tion a notable depression was produced in one portion of a zone

105

corresponding to the circumference of the cornea.* In one case
I have found four times in fifteen minutes the same rhythm ex-
isting in one part of the ciliary muscle. At each of these four
examinations I have found sixteen contractions in one minute.

5. Spontaneous Contractions of the Uterus. — I have seen
hundreds of times the uterus or its cornua, full or empty, contract-
ing to appearance spontaneously, after the death of rabbits and
other animals, at a time when the spinal cord had entirely lost,
not only its reflex power, but also the power of acting on mus-
cles when directly excited by galvanism, by warmth or mechani.
cally.f

I have also seen movements taking place in the uterus and in
its cornua, in recently dead animals, the spinal cord of which I
had destroyed in all its length. The same movements I have
found after I had taken out from the abdomen of a living animal
the whole uterine apparatus. I have found sometimes that after
I had put a ligature around the trachea of guinea pigs, which
were at the end of gestation, parturition took place and was pro-
duced by three causes : 1st, a direct excitation of the spinal cord
by the venous blood ; 2d, a direct excitation of the uterus by that
blood ; 3d, a reflex action of the spinal cord. In two cases I
have seen delivery taking place after the action of one only of
these three cases, namely, the direct influence of black blood on
the uterus of the Guinea pigs, the spinal cord of which I had de-
stroyed from the sixth costal vertebra to the sacrum. The more
complete and sudden is the asphyxia, in a rabbit or a Guinea pig,
during labor, the more certain will the delivery take place.

Dr. Tyler Smith speaks of a peristaltic action of the uterus,
which may expel the child when the mother has died during la-
bor, undelivered. He has not attempted at all to explain that con-

* The eyes had not been opened.

-|-Dr. Tyler Smith, in his very original book on Parturition, (London,
1849, p. 40,) says that "a slow reflex action of the uterus may possibly con-
tinue long after the rhythmic respiratory actions have ceased ; as long, in-
deed, as the body retains its warmth." There is a great error in these lines,
about the relation between the warmth of the body and reflex action. We
may observe reflex actions even in animals that have lost 10, 12 or 15° Cents.,
(18, 22 or 27° Fahr.,) of their temperature, and, in certain circumstances,
these actions may be, then, more powerful than if the temperature of the
body was normal. For instance, if we decapitate an animal after having

106

traction, i. e. to find out its cause and the circumstances which
favor or are opposed to its existence ; besides, he has not demon-
strated that the peristaltic contraction is entirely independent of
the nervous system.

6. Spontaneous rhythmical movements in the crop and oeso-
phagus of pigeons and other birds. — I have found that if the crop
of a bird, and more particularly of a pigeon, is opened during
digestion, some rhythmical movements are frequently seen in it
and in the oesophagus. Ordinarily these movements are perfectly
regular. They begin in the upper part of the crop, and are pro-
pagated from there to the oesophagus. If the animal is asphyx-
iated, these contractions become very energetic. Their ordinary
number, in a minute, varies from ten to twenty.

I have ascertained that these rhythmical movements take
place as well in a crop and oesophagus separated from the animal,
as in these same parts left in situ. Therefore, the nervous cen-
tres are not the source from which originates the excitation which
acts on the muscular fibres to put them in contraction.

7. Spontaneous movements in limbs of persons who have died
of cholera. — It is known that after death by cholera, the whole
body, and more particularly the limbs, have sometimes very con-
siderable movements. In some cases I have seen alternative
movements of flexion and extension of the arms or of the legs,
even three hours after the cessation of the beatings of the heart.
Physicians who know how quickly after death the nervous system
loses its vital powers, will admit easily that these movements can-
not be the result of an action of that system. I have ascertained
on more than sixty bodies of men who died of cholera, or of
various other diseases, that a short time before, or a very short
time after the cessation of the beatings of the heart, no reflex

put a ligature around the carotid and vertebral arteries, we find, when pul-
monary insufflation is made carefully, that two important phenomena take
place — one is a gradual rapid loss of temperature, if the atmosphere is cold,
(this is the well known fact discovered by Sir B. Brodie,) and the other is a
gradual and considerable increase of the reflex faculty. It has been in
such cases that I have found the greatest degrees of reflex power in mam-
mals. The nervous power accumulates to such an extent in the spinal cord,
that if we pinch the skin in any part of the body, but more particularly on
the chest and on the anterior limbs, a reflex respiratory movement takes
place.

107

action was produced by the tickling of the sole of the foot. The
greatest duration of reflex action that I have observed after death
has been in a case of cerebral apoplexy. It has lasted thirteen
minutes after the last breathing, and about eight minutes after
the last beating of the heart. Dr. Bennet Dowler has recorded
many curious facts (observed in cases of death from yellow-fever,
cholera, etc.,) from which he concludes also that the movements
taking place in the limbs are not reflex actions.

I have found that, in general, the more sudden and complete
has been the asphyxia before death, by cholera, the more the
limbs are moved after death. I have found also that it is in pa-
tients who have died during the algid period that these move-
ments are ordinarily found.

These facts, as I will show hereafter, appear to prove that
these movements, like the other movements, of which I have
previously spoken, are excited by carbonic acid alone, or toge-
ther with the poison of cholera.

8. Spontaneous contractions of the bowels, the bladder, the iris
and other parts of the body. — It is known that frequently at the
time of death, many of the contractile tissues of the body are
put into contraction. I can go farther and say that it is so with
all the contractile tissues ; and that, contrary to the general
opinion, a nervous action is not necessary for these contractions.

There are contractions in all the following organs or tissues
during agony and after death : 1, the muscles of animal life ;
2, the sphincter of the anus ; 3, the respiratory muscles ; 4, the
iris ; 5, the digestive canal (in all its length) ; 6, the urinary
bladder ; 7, the uterus ; 8, the scrotum, (dartos) ; 9, the gall-
bladder; 10, the ureters; 11, the seminal vesicles; 12, the
bronchial tubes ; 13, the skin ; 14, the blood-vessels ; 15, the
lymphatics ; 16, the cilia.

As to the skin, in many cases the so-called goose-flesh (cutis
anserina) takes place a little before or little after death, although
the body has not yet become cold. I have seen it vejy strongly
marked on the inferior limbs of a paraplegic who died of a soften-
ing of the dorso-lumbar part of the spinal cord. It results from
this fact that the cellular tissue is able to contract from the same

108

cause which produces contractions at the time of death, in mus-
cular tissues — that is, very likely, carbonic acid.*

Besides, I have found contractions of the cellular tissue of the
skin of the face, in animals killed by asphyxia, and on which the
facial nerve had been divided for many days or weeks.

In the same man who had a paraplegia, and of whom I have
just spoken, I saw very strong contractions in the dartos, during
agony.

In animals suddenly asphyxiated, after the destruction of the
dorso-lumbar part of the spinal cord, the seminal vesicles some-
times contract, and a slow ejaculation takes place, although there
is no erection.

In the sphincter of the anus, when it is paralysed, there are
only slight contractions, but they are evident.

The urinary bladder, during agony or after death, sometimes
contracts so much, even when it is paralysed, that all the urine
it contains is expelled.

The ureters present very strong contractions, in animals
recently killed by asphyxia, and these contractions in some cases
are rhythmical. The same movements are seen when all the
urinary apparatus is in situ, and when it has been removed from
the abdomen, and therefore separated from the nervous centres.
The contraction begins at the kidney and thence is very quickly
propagated all along the ureters to their termination in the blad-
<der. Among the contractile tissues, that of the ureters is one
•of the most irritable.

Bidder and Schmidt, of Dorpat, have recently found that after
the division of the two pneumogastric nerves, there is more car-
bonic acid expelled by the lungs than usual. This fact is very

* Kolliker has recently discovered fibro-muscular cells— that is, mus-
cular fibres of organic life — in the skin, and he maintains that the cutis
<ansertna is produced by these fibres, and not by the cellular fibres. I have
published facts which, I think, prove conclusively that the contractions in
the skin are in a great measure performed by the cellular tissue. (See
Oomptes Rendus de la Soc. de Biologic, 1849, t. i. pp. 134 et 157, et 1850,
t, ii. p. 132.) Since that time, I have found that in some cartilaginous
fishes, in which the iris does not contain any muscular fibre, and is com-
posed of cellular tissue, this membrane may be the seat of considerable
contractions ; so that I consider it as perfectly certain that the cellular tissue
/at least in some organs) is contractile.

109

important, because if the theory, which I am about to propose,
be true, we ought to see a contraction produced in the bronchial
tubes, in consequence of the unusual amount of carbonic acid
that they contain. Now, such a contraction certainly exists then,
and it is it which causes the well-known difficulty in the expan-
sion of the chest, which exists in that case.

In the eyes, even when they are paralysed by the section of
the three nerves of the iris, (the third pair, the sympathetic, in
the neck, and the ophthalmic nerve,) the pupil may, at first, con-
tract and afterwards dilate very much.

The lymphatics and the thoracic duct contract very much after
death. I have, sometimes, in cases where these vessels were
dilated by chyle, introduced a glass tube, two lines in diameter,
into the thoracic duct, and I have seen the liquid ascend into the
tube, and in one case run out, although the tube was five inches
high.

The cilia are known to have movements independent of the
nervous system.

The gall-bladder contracts little and slowly, but evidently,
after death, even when it has been, with the liver, removed from
the abdomen and separated from the nervous centres.

The choledoch duct and the pancreatic duct, as my friend CI.
Bernard has discovered, have rhythmical contractions during life,
in birds. I have found these movements perfectly regular after
I had removed all the viscera from the abdomen. Therefore the
cause of these rhythmical contractions is not in the nervous
centres.

The bowels have considerable contractions during agony and
after death ; and I will prove hereafter that the cause of these
movements is not the influence of cold, or that of air, when they
are exposed to the atmosphere. Nurses, in France, are in the
habit of judging that death has positively taken place, when,
after the cessation of breathing, they see urine and foecal matters
expelled. This expulsion depends upon the contractions then
taking place in the bladder and in the bowels.

9. Causes of the apparently spontaneous contractions during
life and after death. — All the contractions of which I have
spoken, appear to me to be produced by an excitation made upon
the contractile tissues by a substance existing in the blood, and

110

the quantity of which becomes much increased during asphyxia.
The relations between these contractions and asphyxia are evi-
dent. A great many of them do not exist unless asphyxia
exists, and their energy is always in proportion to the degree of
asphyxia.

I believe that the substance in the blood which has that power
is the carbonic acid. In admitting this opinion we can easily
explain all the phenomena.

There are certain contractions which take place in muscles of
animal life, after death, and which have quite another cause. In
the cold seasons, it is not uncommon to find, in limbs of frogs,
when we separate them from the body, apparently spontaneous
contractions, lasting sometimes for half an hour or even more ;
but these contractions have begun when we have cut the nerves,
and they continue on account of galvanic discharges which ac-
company them. The fact that they begin after the excitation of
a nerve, is sufficient to show that they are not like the other con-
tractions, of which I have previously spoken.

Some of the facts I have related may appear to be distinct
from the others. So, for instance, contraction taking place in
paralysed muscles of the face or of the limbs in living animals,
might be considered as quite different from the contractions exist-
ing after death. I think that they originate from the same cause,
viz., an excitation by carbonic acid. A muscle may be moved
or not be moved by an excitant. If the degree of irritability is
greater in one case than in another, we may see the same amount
of excitation produce a movement in the first case, and not in the
second. If the amount of excitation increases, then we may see
both muscles moved, but the most irritable more than the other.
This is sufficient to explain why the paralysed muscles may be
moved by the carbonic acid existing in the blood during life,
while the muscles that are not paralysed are not moved. I have
found that the degree of irritability increases, during a certain
time after paralysis, in the muscles of animal life. Their irrita-
bility being augmented, they are excited sufficiently to contract,
by a quantity of carbonic acid which is not sufficient to act on
the other muscles.

The following facts and reasonings will, I believe, prove that,
at least in the bowels, black blood, very likely by its carbonic

Ill

acid, may excite powerful movements. It is known that when
we open the abdomen of an animal immediately, or a short time,
after death, we generally see considerable movements in the
bowels. These movements have been attributed to the action of
air, or to that of cold, on the bowels. This is not a right view.
A sudden exposure to a cold atmosphere may, possibly, produce
contractions in the bowels ; but certainly cold is not the ordinary
cause of these movements. At first, they may exist in a warm
atmosphere, and then they appear to be more rapid than in a
cold atmosphere. Besides, the bowels may be exposed to a cold
atmosphere, and remain motionless, although they have their en-
tire irritability. As to atmospheric air, it is not able to excite a
movement in the bowels. If we open the abdomen of a living
animal, in avoiding to excite mechanically the bowels, and in al-
lowing the animal to breathe freely, we may for a long time see
no other movement in the bowels, except, sometimes, slight re-
gular and natural peristaltic motions, depending on digestion,
and limited to some small parts of the bowels. The animal must
be kept on his back, and we must avoid touching the bowels, be-
cause a slight contact is sufficient to produce movement. Now,
if we prevent the animal from breathing, we see, after ten, fif-
teen, or twenty seconds, very violent, sudden, and rapid contrac-
tions taking place in all parts of the intestine, from the stomach
to the rectum, but much more in the small intestine than else-
where. These movements are quite different from the digestive
peristaltic movements. If the animal is allowed to breathe again,
and freely, the movements diminish gradually, and disappear
almost entirely after a few minutes. Then, if we prevent it
again to breathe, we see the movements produced again. This
experiment may be repeated many times, with the same result,
on the same animal.

We are certainly entitled to conclude that there is an exciting
cause of contractions, developed during asphyxia, and that it is
neither the cold nor the atmospheric air which produces in all
cases the movements of the bowels after the opening of the abdo-
men. We may draw the same conclusions from another experi-
ment. If we put a tie around the trachea of a living animal,
immediately after expiration, we may see and feel violent move-
ments taking place in the bowels, although the abdomen is not

112

opened. It is in consequence of such movements that there is
an expulsion of faecal matters, after death, in man. The urine
may be also expelled in these cases, in man and in animals, and
this expulsion takes place because the bladder contracts, and not,
as it is generally admitted, because the sphincter vesicce becomes
relaxed.

Some physiologists have considered the cessation of the circula-
tion of the blood in the bowels as the cause of their movements,
after death, and they relate as a proof the fact that the section of
one of the arteries going to a part of the intestines, is followed by
contractions in the parts thus deprived of circulation. But no-
thing is explained by saying that the cause of the contraction is
in the absence of circulation. As contractions require an exci-
tation to be produced, what is the exciting cause when the blood
does not circulate ? After the section of an artery there is blood
remaining in the capillaries, and that blood, after a short time, be-
comes very rich in carbonic acid, and then, if my theory is right,
contractions ought to be produced. The result of the section of
one of the arteries is, therefore, in accordance with my theory.

Other facts may be adduced proving the influence of black
blood and carbonic acid on the bowels.

If black blood is injected in the arteries of the small intestine
when its irritability is much diminished, movements are almost
immediately produced, but they do not last long. On the con-
trary, if red blood is injected, movements do not appear immedi-
ately, and they are very strong and last long. This action of
red blood may be easily understood : it increases the irritability
of the muscular layer of the bowels, as it does for that of the
muscles of animal life, and when it has been changed into black
blood, it excites the muscular tissue and produces contraction.
The strength and the long duration of the contraction in this
case depend on the increase of irritability. When, as in the
above experiment, black blood (containing a great quantity of
carbonic acid, on account of the constant formation of that gas
in blood deprived of the contact of atmospheric air) is injected,
the irritability is not sensibly increased, but the excitation is con-
siderable and there is an almost immediate effect.

If air is injected in the arteries of the bowels, soon after the
death of the animal, a part of the blood it contains is expelled,

113

and we find that the movements do not last as long as if the
blood had not been removed.

When an animal is killed by haemorrhage, the intestine, as well
as all the other organs, contains more blood than usual, and then
its movements are not so strong, and last less than they do gene-
rally.

When in a recently asphyxiated animal the arteries and veins
of a part of the bowels are divided, the movements of that part
become less strong and last less than those of the other parts of
the intestine.

When the bowels of a recently asphyxiated animal are put
under a receiver containing carbonic acid, their movements are
very much increased, but they do not last so long as when they
are in the atmosphere.

When they are put under a receiver containing hydrogen,
their movements are very quickly diminished in strength, and
they last still less than when exposed to carbonic acid.

When they are put in oxygen, their movements diminish a
little at first and soon after become stronger, and they last much
longer than usual.

As a general conclusion about the apparently spontaneous con-
tractions which I have described as taking place in paralyzed
muscles during life or after death, I will say that it seems that
black blood by its carbonic acid is the cause of these contractions.
When the nervous centres are still united with the contractile
tissues, we see, during agony or after death, stronger movements
generally than when they are separated. The action of black
blood on the nervous centres may be very great. I have found
that the spinal cord, when separated from the encephalon, may
be strongly excited by black blood. If an animal is asphyxiated
after a transversal and complete division of its spinal marrow in
the dorsal region, we see convulsions taking place in the poste-
rior limbs, and they are nearly as strong as when the nervous
centers have not been injured. The excitation on the spinal
marrow is considerable enough to produce an erection of the
penis.*

* Almost all, if not all, the secretions of the body are increased during
asphyxia: bile, (as shown by Professor Bouisson,) saliva, tears, gastric,
pancreatic and intestinal juices, and also liver-sugar, etc., are produced in

114

XXXIV. — ON THE CAUSE OF THE BEATINGS OF THE HEART.

The cause of the rhythmical movements of the heart has been
heretofore unknown. I believe I have discovered it.

Before exposing my theory and the facts upon which it is
grounded, I will show that the theories put forward until now
are not correct.

There are three theories only which are worthy of examina-
tion : 1st, that of Haller ; 2d, that of Carpenter ; 3d, that of
Budge, Schiff, and others.

Haller has been very near the truth in admitting that the
beatings of the heart were excited by the blood. His error has
been an error loci. He thought that the blood acted in the
cavities of the heart. It is not so ; and it is known that the
heart may continue to beat after all the blood has been drawn
out of its cavities.

The doctrine of Carpenter* is a very simple and remarkable
one. He believes that the muscular fibres may act without hav-
ing been excited. A muscle, says he, may be compared to the
electric jar, and become so charged with motility , (or motor force,)
as to execute spontaneous contractions ; and elsewhere, " It is not
very difficult to conceive that the ordinary rhythmical movements
of the heart may be due to a simple excess of this motility, which
is continually being supplied by the nutritive operations, and is
as constantly discharging itself in contractile action." Carpenter
believes that the reason for which the heart presents spontaneous
contractions while the other muscles do not, (at least ordinarily,)
is, that there is a higher degree of motility in the heart. He
considers as very important the facts I have discovered, that
many other muscles besides the heart may present rhythmical
movements. He thinks that these facts show there is a tendency
to rhythmical movements in the muscles themselves, altogether

greater quantity then than usual. I believe that this increase results from
the excitation of the nervous system, and, in some measure, perhaps, from
a direct action of black blood on the capillaries of the glands. The urinary
secretion may also be changed in asphyxia, and not only then the urine
may contain sugar, as Alvaro Reynoso has found, but also albumen.

*See his Principles of Human Physiology, American edition, by F. G.
Smith. Philadelphia, 1853. pp. 130 to 132, 319, 325, and 471-72.

115

independent of the excitement to action which they receive
through the nervous system.

The best ground for the hypothesis of Carpenter is that, ac-
cording to him, the heart continues to heat, although it is not
exposed to any excitation in certain circumstances. He says :
"When every source of excitement is excluded, we cannot but
perceive that these actions take place with a spontaniety which
can scarcely be accounted for in any other way than by con-
sidering them as expressions of the vital activity of the compo-
nent cells of these forms of muscular tissue, which manifests it-
self in this mode, when the developmental life of the cell has at-
tained its maturity. And this view is strikingly confirmed by"
what we know of the origin and termination of these movements.
For the action of the heart commences when, as yet, its contrac-
tile parietes consist but of an assemblage of ordinary-looking
cells, no proper muscular tissue being evolved, and no nervous
system being yet developed, from which the stimulus to the move-
ment can proceed ; and it is impossible to assign any other cause
for the movement under such circumstances, than the attributes
inherent in the tissues which perform it."

The first thing to be said against the view of Carpenter is, that
his hypothesis is not necessary ; because it is possible to assign
another cause for the movement of the heart under the circum-
stances he speaks of. This will be proved hereafter.

The doctrine of Carpenter implies, that the degree of irrita-
bility (motility, motor force, contractility, — never mind the
name) is greater in the heart than in the other muscles which
have no spontaneous action. This is not the case. The degree
of irritability, as judged by its duration after death, is generally
greater in the muscle of animal life, than in the heart. The ac-
cepted sentence of Haller, Cor ultimum moriens, generally, is
not true.

If Carpenter was right, we should see, during life, the appa-
rently spontaneous contractions which take place in all the con-
tractile tissues after death ; because their irritability is at a
higher degree in the first, than in the second case. Besides, we
should not see oxygen, or red blood, diminish the frequency of
the beatings of the heart ; and black blood, or carbonic acid, in-
crease that frequency.

116

An experiment, consisting in the research of the influence of
vacuo on the heart, has been made by Tiedemann and by Dr.
S. W. Mitchell, and Dr. T. H. Bache, (see Dunglison's Physiol.,
vol. ii. p. 150.) It seems to me that the result of this experi-
ment is in complete opposition to the doctrine of Carpenter.
These experimenters have found that the beatings of a heart were
speedily brought to a stand by the exhaustion of the air, and
that they were renewed when it was re-admitted. If the view
of the eminent British physiologist was right, we ought to see
the heart continue to beat in vacuo about the same length of time
as it would in hydrogen or nitrogen, because its irritability
•cannot be suddenly diminished enough by the exhaustion of the
air. In these gases the heart of a mammal may beat for five or
ten minutes or more, and the right auricle may beat for hours ;
and the heart of a frog may beat for one day. It is much more
to account for the stopping of the heart's action in admitting that
the excitant of that action is removed during the exhaustion of
the air. John Reid had found that the heart of a frog had con-
tinued to beat in vacua, but how long he does not say.*

I will relate hereafter many experiments of mine which are in
opposition to the theory of Carpenter.

It is one of the most important questions in physiology, whether
the nervous centres, the nerves, and the contractile tissues are
able to act without stimulation. This question has not been
yet entirely treated by any physiologist. I propose publishing
a special paper on the subject. I will merely say here that there
may be apparently spontaneous actions in the spinal cord, as well
as in the muscles. For instance, very frequently, in a frog, after
the removal of the brain and the medulla oblongata, we may see
strong movements apparently spontaneous, but when we know
that the slightest excitation of the skin, or of any other very sen-

* Art. Heart, in Todd's Cyclop., vol. ii. p. 611. J. Reid says in the same
page, "We ought to be more cautious in admitting the existence of this in-
nate moving power, since it is in opposition to a well known law in the
animal economy, that though the various tissues of an organised body are
endowed with certain vital properties, yet the application of certain exter-
nal and internal stimuli is necessary to produce their manifestations of
activity. In fact it is from the action and reaction of these tissues and
excitants upon each other that the phenomena of life result."

117

sitive part, may excite the spinal cord, and produce a reflex ac-
tion, we are authorised to consider all the movements taking place
as reflex actions. An excitation may have come to the spinal
marrow from the bladder, from the bowels, from the lungs, (in
which worms are almost always found in the cold seasons, i. e.
at the time these phenomena are generally observed,) etc.

As to the spontaneity of action in muscles, I have tried to
prove ia a preceding article that it is a mere and false appear-
ance.* I will prove hereafter that the cause of the apparently
spontaneous contractions of the heart, is the same as that of the
like contractions in other contractile tissues.

The physiologists who maintain that the beatings of the heart

* Carpenter says that the action of the uterus, as it shows itself, " not
merely in the final parturient effort, but in local contractions that frequently
occur during the latter months of gestation, (simulating the movements of
the foetus,) are more satisfactorily accounted for by considering them as a
discharge of accumulated power, than in any other mode." I will try to
prove elsewhere that for the uterus, as well as for any other contractile
tisue, there is no spontaneous action. The uterus, in pregnancy, becomes
more and more irritable every day, and when its irritability has arrived at
a very high degree, then the slight excitation produced by the carbonic
acid normally contained in the blood is sufficient to put it in action. When
the contractions have begun, they are very much increased by a reflex ac-
tion. Every contraction is accompanied by a galvanic discharge on the
nerves in the neighborhood of the muscular fibres which contract, and the
sensitive nerves being thus excited, it results, 1st, that a pain is felt, the
degree of which is in proportion to the degree of any contraction, and
therefore with the degree of galvanic discharge ;f 2d, that the spinal mar-
row is excited, and produces reflex movements in the uterus. Now, the
more these reflex contractions are energetic, the more they are induced to
take place again, on account of the galvanic discharge which accompanies
them. So that there would be a constant increase in the intensity of the
contractions if there were not four limits to them. 1st, there is no
galvanic discharge when the muscular fibres are contracted; it is only
at the time they are contracting that this discharge takes place ; 2d, the
primitive cause of contraction, the excitation of the muscular tissue, by car-
bonic acid, diminishes much during the contraction, because the caliber of
the small blood-vessels is much diminished, and the blood expelled from
them ; 3d, every contraction of the uterus diminishes the degree of its irri-
tability ; 4th, the reflex power of the spinal cord becomes exhausted, or at
least diminished.

t See, on this subject, my paper in the Comptes rendus de la Soci4te de Bologne, en. 1850, t. ii
p. 172.

118

depend on the nervous system, appear to me to be greatly mis-
taken. They make a confusion between two things, greatly dis-
tinct, one from the other : they conclude from the fact that the
nervous system is able to act on the heart, that its influence is
necessary. It is the same kind of mistake which is so frequently
made as to the influence of the nervous system on nutrition, on
secretions, and on animal heat ; because that system is able to
act upon these functions, it is concluded that its influence is ne-
cessary.

The first argument to be adduced against the writers who ad-
mit, as necessary, the influence of the nervous system on the
heart, is, that they change only the ground of the difficulty in
doing so. Instead of having to explain why the heart acts rhyth-
mically, they have to explain why the nervous system acts rhyth-
mically on the heart. Not only they have not explained this
rhythmic action of the nervous system, but, as far as I know,
they appear not to have been aware that this was to be explained.

The second reason I will mention, is the fact, so well esta-
blised by my friend Professor Lebert, that, in embryos, the heart
beats when it is merely composed of cells, and when the nervous
system has not yet appeared

A third reason is, that, either in monsters, or in animals ope-
rated on by physiologists, there has been a long persistence of the
beatings of the heart when a part of the cerebro-spinal centre did
not exist, or had been removed. Any part may be in that case,
even the medulla oblongata, as I have discovered. (See Art. xvi.
p. 40.)

In opposition to the idea that the beatings of the heart depend
on the microscopical ganglia existing in that organ, I will say,
that, besides the fact that the heart beats in embryos before the
nervous system exists, and besides the improbability that such a
small amount of nervous matter should have so great a power,
there are two good reasons against this strange theory : —
1. There have been found no ganglia, large or microscopical, in
the auricles, in the sinuses of the pulmonary veins, or in those
veins. All these parts, nevertheless, may continue to beat a long
while, (even for hours,) after they have been separated from the
ventricles where are the microscopic ganglia. 2. Rhythmical
movements may exist in a'great many other muscular parts of the

119

body, where there is no microscopical ganglion, and where these
parts have ceased to be under the influence of the nervous centres.

The three theories which I have examined being unable to ex-
plain the beatings of the heart, I will now expose my theory,
and discuss the three following questions : — 1. What is the exci-
tant which puts the heart in action ? 2. Does that excitant act
rhythmically ? 3. Does that excitant act together directly on
the muscular fibres of the heart, and on the nervous system ; or
does it act only on the muscular fibres ?

After having solved these three questions, I will examine the
objections which might be made to the doctrine I propose.

1. What is the excitant which puts the heart in action ?

I believe that the beatings of the heart are excited by a prin-
ciple existing in the blood, and that carbonic acid is that princi-
ple. This view is grounded on the following facts :

a. When we prevent a warm -blooded animal from breathing, the
beatings of the heart become more frequent than before, for about
one or two minutes. It is not on account of the emotion alone
that it is so, because the same effect is produced when we as-
phyxiate suddenly an animal which has entirely lost his power
of having emotions, in consequence of the action of chloroform.

b. Many times I have found, on myself and on one of my
friends, that the beatings of the heart are rendered more active
during asphyxia. We hold our breath for about three quar-
ters of a minute, and during the last fifteen seconds the heart
beats from two to four (in one case five) minutes more than when
the respiration was free. We have made the experiment in the
sitting position, avoiding any movement of the body in all the
cases.

c. John Reid has discovered that when any hemadynamometer is
put in the femoral artery of a dog, the mercury rises in the in-
strument if the animal is asphyxiated, and about one minute after
the respiration has been stopped. The same result has been ob-
tained in twenty experiments. It seems to me that this fact
proves that the contractions of the heart become more energetic
during asphyxia. John Reid attributes the result he has obtained
to some difficulty that black blood seems to have in passing through
the capillaries of the different parts of the body. I do not deny
that there is such a difficulty ; but I think that the great reason

120

of the ascension of mercury in the hemadynamometer is, the in-
crease in the force of the heart. A simple experiment proves
that I am right. I adapt the hemadynamometer to the aorta in
the abdominal cavity, and then I open quickly the chest, and I
put a ligature to the brachial and carotid arteries. About three
quarters of a minute after opening the chest, and about half
a minute after the ligature has been put on the arteries of the
head and arms, the mercury rises notably in the instrument ;
sometimes the elevation is as considerable as two inches. It re-
sults from this experiment, that the heart beats more strongly in
asphyxia about one minute after its beginning.

d. Woodall, a most intelligent and accurate observer, says Dr.
Martin Paine, (see Med. and Physiol. Comment., t. ii. p. 49,)
states, that the best remedy for syncope is to obstruct respiration
entirely by momentarily confining the nose and mouth. If this
be true, it is in perfect accordance with my view, that, during as-
phyxia, the normal cause of the beating of the heart increases in
the blood.

e. If a frog is put under a receiver containing pure oxygen, at
a temperature of 40 or 50° Fahr. (4, 5, or 10 Cent.) after its
heart has been laid bare and its central nervous system destroyed,
we see the heart beat for a very long time, (one, two, or three
days.) On the contrary, if, at the same temperature, another
frog, deprived also of the central nervous system, is put in car-
bonic acid gas, the heart beats very quickly at first, but it soon
ceases to beat, (in one or two hours only, sometimes, and for the
most about half a day.)

/. All the causes which increase the formation of carbonic acid
gas in the body, increases the frequency of beatings of the heart.

g. If we inject the serum of blood into the arteries of the heart,
so as to expel as completely as possible the blood contained in the
capillaries of this organ, and if then we remove the blood from
the cavities of the heart, we find that its beatings are, at once,
almost entirely suspended, and that they are completely stopped
in a very short time, (from one to eight minutes.) The muscu-
lar irritability is not destroyed in this organ ; it does not beat
because its excitant has been removed.

h. I have found that when the heart of a young animal is put
in hydrogen, its beatings hardly change at first, but they stop in

131

a very short time. When it is put in carbonic acid gas, its beat-
ings are, at first, increased in frequency and strength ; but they
very soon are stopped. When it is put in oxygen, its beatings
are slowly increased in frequency and strength, and they last
very long.

i. On newly-born cats and dogs, before the occlusion of the
ductus jarteriosus, I open the chest and put a ligature on the ar-
teries going to the head and fore limbs, and on the aorta imme-
diately after the origin of the ductus arteriosus. Then the blood,
expelled from the right ventricle, is sent to the lungs, from which
it comes to the left auricle, and afterwards to the left ventricle.
From there it is sent into the only part of the aorta remaining ac-
cessible, and thence it goes into the cardiac arteries, and into the
pulmonary artery, through the ductus arteriosus, (a direction which
is the reverse of the normal direction in that duct.) By the cardiac
veins the blood arrives again in the right side of the heart. The
circulation from the heart to the lungs, and vice versa, continues
very well. I have found, that if hydrogen is insufflated into the
lungs, the beatings of the heart are not much changed at first,
but they go on diminishing, and they disappear in a short time.
When an injection is made with carbonic acid, the beatings of the
heart are quickly increased in frequency and strength ; but they
are stopped after a short time. When oxygen is insufflated, the
beatings of the heart become slowly more frequent, and they re-
main quick and strong for a long time. (I have once, by such
insufflation of oxygen, maintained beating for eleven hours in the
heart of a young cat.)

I believe that these facts prove that black blood, by its car-
bonic acid, is an excitant of the beatings of the heart. If, now,
we adduce to these facts all those I have related in a preceding
article, on the apparently spontaneous contractions in all the
contractile tissues of the body, we shall have a very considerable
number of facts, proving that, during asphyxia, there is an ac-
cumulation in the blood of the principle which causes these con-
tractions. I believe that it is almost impossible to deny that this
principle is the carbonic acid gas-
Before trying to show that what takes place in asphyxia in
the heart is only an exaggeration of what normally exists in that
organ, I will treat the two remaining of the three questions I

122

have announced I would endeavor to solve, as regards the exci-
tant of the heart's action.

2. Why does that excitant act rhythmically ?

I believe it is easy to explain why the agent of excitation of
the heart* produces rhythmical contractions. I will suppose, first,
that the action is permanent. A part of the heart, ventricles, or
auricles, 'being dilated, receives an excitation in all its fibres si-
multaneously, and a contraction is produced. But, according to
the well-known law of Schwann, the exciting cause which is able
to give the impulse when the muscular fibres are long, is not able
to maintain the contraction when the fibres have been shortened.
Then, on account of this insufficiency of power of the cause of the
contraction, a dilatation ensues. We may present the fact in
other words, and say that the resistance to the contraction origi-
nating from the displacement of the constitutive matter of the
contractile tissues, increases in proportion to the shortening of
the fibres ; and that after the fibres have contracted under the
impulse of the exciting cause, although this cause continues to
act, a dilatation is produced by the force belonging to that re-
sistance, which is nothing but elasticity. If the cause of the con-
traction of the heart was a considerable one, then we should see
a permanent .contraction ; and it is so when we apply galvanism —
the elasticity, then, is not powerful eno-ugh to produce dilatation.
On the contrary, with a weak exciting cause, like earbenic acid,
the result ought to be different. When that cause has more
power, as in asphyxia, the shortening of the fibres takes place
quicker, and is more considerable ; and even then it is not suffi-
cient to maintain contraction, the tendency to dilatatioa being
also increased.

I ought to say, that the excitant cause of the contractions is
not always at the same degree of power. The small blood-vessels
and the capillaries being compressed diiring the muscular con-
tractions, there is a diminution of excitation during that time.
This should be sufficient to explain the alternate contractions
and dilatations. But such a diminution in the caliber ought to
be very little, if even it exists in certain organs, (the heart when
composed of cells, for instance.)

•* Whal I will .gay here for the heart, might be said for all the .contractile
tissues, presenting apparently spontaneous rhythmical contractions, as the
eiiia, for instance.

123

I come now to the third question about the excitant of the
heart —

3. Does that excitant act together on the muscular fibres and
on the nerves of the heart, or does it act only on the muscular
fibres ?

I believe at ought to act also on the nerves ; but I cannot prove
it otherwise tthan by saying, that all the agents of excitation that
we know to .act on the muscular fibres, are able to act on the
nerves.

There are many things to be said besides the above facts and
reasoning, to prove the truth of the doctrine I propose. I will
expose some of them.

The following question might be made :

How is it that the heart is the only muscle containing striated
fibres, which presents normally rhythmical movements ?

^ The answer to this question appears to be very simple. The
intensity of the stimuli, the degree of irritability, and the resist-
ance which a muscle has to overcome when it contracts, are three
elements which we ought not to lose sight of when we examine
the difference of contractions between two muscles. Suppose the
heart possessing the same degree of irritability as another mus-
cle : if the stimulus is the same, and the resistance the same also,
for the heart and for the other muscle, there will be the same
effects. But if the stimulus is more considerable in the heart
than in the other muscle, and if the resistance to be overcome is
less for the heart, then with the same degree of irritability in
both parts, and even with less irritability in the heart than in the
other muscle, we wiM see a movement in the heart, and not in
that other muscle. Now a simple examination of the vessels of
the heart, proves that they contain more blood, and consequently
more stimulus, than the other striated muscles. Besides, as the
heart is not inserted into heavy bones to be moved, it has less re-
sistance to overcome when it has not to circulate the blood, as
after death, or when it is out of the chest, than the muscles of
animal life. Some muscles in the face and the diaphragm, being
almost without an external resistance, when their contractions
do not go so far, it results that they are moved much more easily
after death, than the muscles of the limbs. In consequence of
these views, I believe that, although there is in die blood-vessels

of all the muscles of the body a principle which is an exciting
cause of contractions, there are no contractions produced, be-
cause the quantity of that principle is not sufficient, or because
the resistance to contractions in many muscles is greater than in
the heart.

I must, in conclusion, say, that I do not advance my theory of
the rhythmical movements as perfectly proved. I believe it is
true, and that there are a great many facts which appear posi-
tively to prove it. What I can assert is, that it is by far much
more in harmony with all the known facts, than the other theories.

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OCT 22 1992

1NTERUBRARY LOAN

APR .2 9 1993

JAN 0 2 2006

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